# Assembled with the script 'compile.pss' start: # # pars/compile.pss # # This is a parse-script which compiles parse-scripts (!). # # What is more, it can compile itself... so we can do # >> pep -f compile.pss compile.pss > asm.new.pp # # This is useful because the resulting 'assembler' program (in sav.pp) # and printed to stdout, can be used as a replacement for 'asm.pp' # which is the default parse-script language compiler. The advantage # is that it is easier to maintain and add new sytax to compile.pss # than it is to 'asm.pp'. # # This script uses the virtual machine and engine implemented at # http://bumble.sf.net/books/pars/object/ It implements a script language # with a syntax reminiscent of sed and awk (much simpler than awk, but # more complex than sed). # # This code was created in a straightforward manner by adapting the # "assembled" code in 'asm.pp'. Some extra error checks were added. # Also, the EOF test was placed at the end of the script to remove # the 'last character' bug. It was evident that using the script # language is much more comfortable that hand-coding parse machine # assembler programs. # #HOW TO ADD A NEW COMMAND TO PEP # # In general, we would like to avoid adding new commands # (instructions) to the pep script-language/machine since we would # like to keep the machine and language as simple as possible. # However, after great thought and cogitation, sometimes new commands # or features seem like a good idea. To add a new command the # process is as follows: # # Add a constant in command.h and command.c in the info[] array. # Implement the commmand in machine.interp.c in the big switch # statement. Type "make" in the object/ folder to compile the code. # Test the new code in the pep interpreter with # >> pep -Ii "some text" # and type the new command. # # Then modify compile.pss to recognise the command when it is # in a script. # Then copy asm.pp to asm.old.pp Important!! be careful to save # a working copy of "asm.pp" or else the whole system stops working! # # Then do # >> pep -f compile.pss compile.pss > asm.new.pp # >> cp asm.new.pp asm.pp # >> vim asm.pp # (and delete the 2 extra print commands - search for "remove" # Now test your "newcommand" with eg # >> pep -e "r; newcommand; t;d;" -i "abcd" # If pep stops working completely, you will need to copy asm.old.pp # back to asm.pp to get things working again. # # Now, if you wish, add the new command to the various # translation scripts in the tr/ folder. The modifications # required in the translation scripts are very similar to the # modifications made to the "compile.pss" script, except that # the target language is different. # #REPLACING ASMPP # # We can use this script as a replacement for "asm.pp" or # "asm.handcode.pp" which is a script assembler written by hand in # the parse machine assembly format (1 command per line, labels, jumps, # tests, etc). # # * replace asm.pp with compile.pss # ----- # # generate the new script assembler # cp asm.pp asm.old; pep -f compile.pss compile.pss > asm.new.pp # cp asm.new.pp asm.pp # # test the new assembler (the script "r;t;t;t;d;" will be compiled # # by the new asm.pp which we have just created. # pep -e "r;t;t;t;d;" -i "abcd" # # output: aaabbbcccddd # ,,, # # The advantage of all this, is that it is much easier to maintain and add # new syntax to "pars/compile.pss" than it is directly, to "pars/asm.pp" # # For example asm.handcode.pp still uses "rabbit hops" to compile "quoteset" # tokens (an old version of the "ortestset" token), which is very inefficient # but compile.pss uses the new look-ahead technique. Also, there are negated # tests implemented in compile.pss but not implemented in asm.handcode.pp # # I will no longer continue to maintain asm.handcode.pp because its real # purpose was to "bootstrap" the current script. I will maintain working # copies of asm.pp as generated by this script in case of future errors. # #NOTES # # The accumulator register was being used to generate true-jump # targets for testsets, but no longer # # This script can be used as the basis for many others which transform # scripts in some way. # # For example, to 'pretty-print' scripts, or to generate compilable c code # for a script using the functions in machine.methods.c. So, instead of # compiling to the "assembler" format for the machine (which is then # interpreted by the code in pep.c) we can compile to a series of c function # calls. This is c source code which can be compiled with gcc, producing an # executable version of the target script. # # This is an interesting idea, because we can transform a script into # compilable or executable code in a different language with a different # 'Machine' object. So, for example, we could write a Machine object in Ruby # or Java or Python or x86 assembler and then generate compilable or # executable code for that target environment. The compilable code would # consist of a series of method calls for the given object and test and # jumps. # # It will also be interesting to see if there is a significant performance # advantage in running executed, rather than interpreted scripts. see # tr/translate.c.pss or tr/translate.go.pss for creating executable parse # programs from scripts # #GRAMMAR NOTES # # The machine cannot directly implement the ebnf structures of repetition # "{...}", optionality "[...]" or grouping "(...)", so we need to express all # grammar rules only in terms of alternation |. Quotesets are a handy way to # express this in a script, eg # # * bnf rule: alpha ::= a | b | c ; # >> 'a','b','c' { clear; add "alpha*"; push; .reparse } # # It is sometimes straightforward to factor out the above ebnf structures, # but the result is a greater number of rules. # #SEE ALSO # # At http://bumble.sf.net/books/pars/ # object/pep.c # the current implementation of the machine interpreter and debugger. # object/*.c # the virtual machine and components # tr/translate.java.pss # compiles pep scripts to a stand-alone java source code file # tr/translate.go.pss # tr/translate.ruby.pss # tr/translate.python.pss # As above, for go, ruby and python. # asm.handcode.pp # a handcoded "assembly" compiler of the parse script language for # a previous version of the script language. This was how I # initially "bootstrapped" the pep language (before using the # current file, compile.pss to create new versions of the pep # language). # #USAGE # # This script is used to replace the hand-coded assembler file # "asm.handcode.pp" since it is much easier to maintain and add new syntax # for the parse-script language. Comments are preserved (largely) in the # output file. # # We can also do the seemingly strange operation # >> pep -f compile.pss compile.pss # which actually creates an 'assembler' version of itself in 'sav.pp' # which is then be suitable for use as an 'asm.pp' substitute. # (This is how we modify the syntax of the pep language, if need be). # This is quite tricky to think about since it is so self-referential. # # This is analogous to the equally strange operation # >> pep -f tr/translate.c.pss tr/translate.c.pss > eg/clang/tr.clang.c # which generates a compilable c language program of the compilable # script. # # It is possible to compile this script into a stand-alone # executable with: # ---- # pep -f tr/translate.c.pss tr/translate.c.pss > eg/clang/tr.clang.c # cd eg/clang/ # gcc -o tr.clang.c -Lobject -lmachine -Iobject # ,,,, # #TESTING # # * view how this script compiles an inline script # >> pep -f compile.pss -i "[aeiou] {a '(vowel)'; } t;d;" # # The result will also be saved in "sav.pp" # # * see how the compiled script runs # >> pep -a sav.pp -i "abcde" # output: a(vowel)bcde(vowel) # # * test "test chaining" compilation # >> pep -f compile.pss -i "r;'a','b','c'{t;}t;d;" # >> pep -a sav.pp -i "axbxcx" # output should be: aaxbbxccx # # * view/debug how compile.pss compiles test chains (or something else) # >> pep -If compile.pss -i "r;'a','b','c'{t;}t;d;" # # This provides interactive debugging of the compilation process. # #FIXED BUGS # # I was getting segmentation faults because of one-off errors etc # >> pep -f compile.pss compile.pss # Mainly fixed with "valgrind", but still a bug in "until" (in # object/machine.interp.c execute()... need to implement endsWith() function. # And one other bug. # * didnt need 2 jumps after "tests", just 1 jumpfalse or jumptrue # used "replace" to remove the unnecessary jump # # * eg: add "\\"; threw an error and also: replace "\\" "\\\\"; # This was a problem with the "until" implementation in machine.interp.c # It was actually necessary to count the number of escape chars # before the suffix. If even, break, if not, dont. # #BUGS # # * missing braces in scripts dont produce good error messages, # just a cryptic "script could not be compiled". # # * should I unescape single quotes in single quote blocks?? # eg ' abc\'xyz' will become " abc'xyz" # # * doesnt catch B[abc] or E[a-z] type errors in scripts. Also # doesnt catch "r;r;d" type errors. # * Also, un-balanced braces give cryptic error messages # # compile.pss should not write the compiled script to stdout # because then asm.pp will do the same thing. easy enough to fix # in asm.pp as well (comment out final 2 "print" commands). # # Comments may not be parsing correctly. # # Comments and multiline comments should not jump back to read # after deleting the comment, because there could be no more # input, and read will throw an error. They should jump to # the EOF end-of-file check. Or they could just call ".reparse" # which is safe but not very efficient. # #TODO # # Add an "echar" command that changes the default escape # character. Also, in some languages a character actually # escapes itself, eg '' is ' escaped! # # We could allow single argument "replace" command eg: # >> replace "x"; # which is equivalent to # >> replace "x" "": # # Need to catch multiline quote errors when used with the # "until" command. # # Separate error checking into a new script, and make pep load # an assembled version of this error checker. This will allow # the same error checker to be used with the scripts # tr/translate.java.pss tr/translate.tcl.pss etc. # #HISTORY # # 31 aug 2022 # implemented until; (untiltape) which reads until the # workspace ends with the current tape-cell. # 19 aug 2022 # Need to add "esc" to change default escape char. # "write " to write to a given file # "quit " to exit with an error code. # Try to change the grammar to allow expression syntax # as in tr/translate.perl.pss Need to make better # error checking. # # 15 june 2021 # Adding the commands "upper" "lower" and "cap" # "nochars" "nolines" # # 13 march 2020 # Added compilation for multiline arguments for the "add" # command. Appears to be working. # # 15 sept 2019 # Realised that I can have an eof error check block at # the end of the script just before all the tokens are # pushed back on the stack. See the 1 and 2 token eof error # check in this script. # # 13 september 2019 # Adding "mark" and "go" commands here. # Improved unterminated quote '/" error messages. In general # it is much more helpful to catch the error when it happens # and print an informative message (with line-number etc). # # 5 september 2019 # # Added a "stack" and "unstack" command to the machine and # to compile.pss # # 29 august 2019 # # Improved some error checks. Could make the error check code # more succinct. # # Changed the way testeof and testtape are parsed to include # them with other tests. This also allows to negate them with # !(==) and !(eof) and also to concatenate with other tests # eg: (eof),B"abc" {} # added extra syntax and <==> for these tests. # # 25 august 2019 # # Realised that I dont need 2 jumps for OR test concatenation (with ',') # That will greatly improve script interpretation efficiency. # # Added AND concatenation logic to tests so now we can do # # * test if workspace begins with 'a' AND ends with 'z' # >> B"a".E"z" {} # # Changed the way .reparse and .restart are parsed and compiled. # These are now parsed as 2 tokens ".*word*". This allows me to # use '.' for AND logic concatenation in tests. It also allows # me to provide special semantic meaning to commands beginning with # a dot, which seems like a good thing. # # Added "delim" command here and in machine.c and machine.interp.c, # to change the stack delimiter. # # 24 august 2019 # # The "state*" token should be separated into "testeof*" and # "testtape*" and then the 2 tests can be elided.(done) # # The conversion to a "test*{*" rule and ellision of # multiple tests will make this script much more compact and hopefully # just as readable. Also, as a side effect, negation of all # tests will be available soon. Also, it is possible to chain together # different types of tests. # # Converted quoteset to "ortestset*" and "andtestset*". # I will introduce a new notation namely: # # * check if workspace begins with "abc" AND ends with "xyz" # >> B"abc" . E"xyz" { commands } # # so the dot will become an "AND" (&&) concatenator of tests # and "," will remain as the "OR" (||) concatenator of tests # In these || and && test lists any type of test can be # included for example # # * check if workspace starts with "a", only contains chars a|b|c # * and ends with the letter "z" (using "." AND concatenator) # >> B"abc" . [abc] . E"z" { ... } # # Experimenting with the new technique to create negated tokens # classes. # # * test negated tokens for the equality test # >> pep -f compile.pss -i 'r;!"b",!"a"{nop;}' # # 23 august 2019 # # Adding begintests B"..." { } and endtests E"..." {} to the quoteset logic. # But need to juggle the combinations. Also will add classes and negated # classes. More or less working. But should actually change parsing to # make quotesets more flexible, see the section of the script for details. # # The new quoteset compilation seems to be working. # Needs more testing. We can now use compile.pss as a replacement # for asm.pp. # # Converting to a new quoteset (eg: 'n','m' {...} ) lookahead compiling # technique. Also we can compile comments with rules for # "comment*command*" and "command*comment*" and "comment*comment*" -> # "comment*". Instead of the current shenanigins. # # 14 august 2019 # # trying to preserve comments here but cant reduce comments # with tokens like {* }* !* etc because we never retrieve # the attributes for those tokens. more thought required. # # Added a !"text" {...} syntax. very simple to add here. # did the same in compilable.c.pss # # Added a "begin" block to this (for start configurations of scripts). # Also need to improve the compilation of "quoteset*" tokens which produce # nifty but very poor code. need 'tapereplace' command for this? # # 30 july 2019 # Fixed the last character bug by putting the EOF test at the very end of # the file. The translation is complete and the script appears to be # working but no doubt will contain bugs. Initially translated from # asm.pp. # # read #-------------- # make character number relative to line number for # compile error messages etc. # this is causing pep to hang/ infinite loop? not sure why #"\n" { clear; nochars; (eof) { .reparse } .restart } # [:space:] { clear; (eof) { .reparse } .restart } testclass [:space:] jumpfalse block.end.15710 clear jump parse block.end.15710: #--------------- # We can ellide all these single character tests, because # the stack token is just the character itself with a * # Braces {} are used for blocks, ',' and '.' for concatenating # tests with OR or AND logic. 'B' and 'E' for begin and end # tests. testis "{" jumptrue 16 testis "}" jumptrue 14 testis ";" jumptrue 12 testis "," jumptrue 10 testis "." jumptrue 8 testis "!" jumptrue 6 testis "B" jumptrue 4 testis "E" jumptrue 2 jump block.end.16072 put add "*" push jump parse block.end.16072: #--------------- # format: "text" testis "\"" jumpfalse block.end.16425 # save the line number in case there is no terminating # quote. clear ll put clear add "\"" until "\"" testends "\"" jumptrue block.end.16367 clear add "Unterminated quote (\") starting at line " get add " !\n" print quit block.end.16367: put clear add "quote*" push jump parse block.end.16425: #--------------- # format: 'text', single quotes are converted to double quotes # but we must escape embedded double quotes. testis "'" jumpfalse block.end.16971 # save the line number in case there is no terminating # quote. clear ll put clear until "'" testends "'" jumptrue block.end.16800 clear add "Unterminated quote (') starting at line " get add "!\n" print quit block.end.16800: # should we unescape single quotes here?? clip escape "\"" put clear add "\"" get add "\"" put clear add "quote*" push jump parse block.end.16971: #--------------- # formats: [:space:] [a-z] [abcd] [:alpha:] etc testis "[" jumpfalse block.end.17119 until "]" put clear add "class*" push jump parse block.end.17119: #--------------- # formats: (eof) (==) etc. I may change this syntax to just # EOF and == testis "(" jumpfalse block.end.17628 clear until ")" clip put testis "eof" jumptrue 4 testis "EOF" jumptrue 2 jump block.end.17313 clear add "eof*" push jump parse block.end.17313: testis "==" jumpfalse block.end.17366 clear add "tapetest*" push jump parse block.end.17366: add " << unknown test near line " ll add " of script.\n" add " bracket () tests are \n" add " (eof) test if end of stream reached. \n" add " (==) test if workspace is same as current tape cell \n" print clear quit block.end.17628: #--------------- # multiline and single line comments, eg #... and #* ... *# testis "#" jumpfalse block.end.18677 clear read testis "\n" jumpfalse block.end.17764 clear jump parse block.end.17764: # checking for multiline comments of the form "#* \n\n\n *#" # these are just ignored at the moment (deleted) testis "*" jumpfalse block.end.18523 # save the line number for possible error message later clear ll put clear until "*#" testends "*#" jumpfalse block.end.18268 # convert to # single-line comments clip clip #put; clear; add "#*"; get; add "*#"; replace "\n" "\n#" # create a "comment" parse token put clear add "comment*" push jump parse block.end.18268: # make an unterminated multiline comment an error # to ease debugging of scripts. clear add "unterminated multiline comment #* ... *# \n" add "stating at line number " get add "\n" print clear quit block.end.18523: # single line comments. some will get lost. put clear add "#" get until "\n" clip put clear add "comment*" push jump parse block.end.18677: #---------------------------------- # parse command words (and abbreviations) # legal characters for keywords (commands) testclass [abcdefghijklmnopqrstuvwxyzBEKGPRUWS+-<>0^] jumptrue block.end.19058 # error message about a misplaced character put clear add "!! Misplaced character '" get add "' in script near line " ll add " (character " cc add ") \n" print clear bail block.end.19058: # my testclass implementation cannot handle complex lists # eg [a-z+-] this is why I have to write out the whole alphabet while [abcdefghijklmnopqrstuvwxyzBEOFKGPRUWS+-<>0^] #---------------------------------- # KEYWORDS # here we can test for all the keywords (command words) and their # abbreviated one letter versions (eg: clip k, clop K etc). Then # we can print an error message and abort if the word is not a # legal keyword for the parse-edit language # make ll an alias for "lines" and cc an alias for chars testis "lines" jumpfalse block.end.19642 clear add "ll" block.end.19642: testis "chars" jumpfalse block.end.19674 clear add "cc" block.end.19674: # one letter command abbreviations testis "a" jumpfalse block.end.19741 clear add "add" block.end.19741: testis "k" jumpfalse block.end.19771 clear add "clip" block.end.19771: testis "K" jumpfalse block.end.19801 clear add "clop" block.end.19801: testis "D" jumpfalse block.end.19834 clear add "replace" block.end.19834: testis "d" jumpfalse block.end.19865 clear add "clear" block.end.19865: testis "u" jumpfalse block.end.19896 clear add "upper" block.end.19896: testis "U" jumpfalse block.end.19927 clear add "lower" block.end.19927: testis "A" jumpfalse block.end.19956 clear add "cap" block.end.19956: testis "t" jumpfalse block.end.19987 clear add "print" block.end.19987: testis "p" jumpfalse block.end.20016 clear add "pop" block.end.20016: testis "P" jumpfalse block.end.20046 clear add "push" block.end.20046: testis "u" jumpfalse block.end.20079 clear add "unstack" block.end.20079: testis "U" jumpfalse block.end.20110 clear add "stack" block.end.20110: testis "G" jumpfalse block.end.20139 clear add "put" block.end.20139: testis "g" jumpfalse block.end.20168 clear add "get" block.end.20168: testis "x" jumpfalse block.end.20198 clear add "swap" block.end.20198: testis ">" jumpfalse block.end.20226 clear add "++" block.end.20226: testis "<" jumpfalse block.end.20254 clear add "--" block.end.20254: testis "m" jumpfalse block.end.20284 clear add "mark" block.end.20284: testis "M" jumpfalse block.end.20312 clear add "go" block.end.20312: testis "n" jumpfalse block.end.20343 clear add "count" block.end.20343: testis "+" jumpfalse block.end.20371 clear add "a+" block.end.20371: testis "-" jumpfalse block.end.20399 clear add "a-" block.end.20399: testis "0" jumpfalse block.end.20429 clear add "zero" block.end.20429: testis "c" jumpfalse block.end.20457 clear add "cc" block.end.20457: testis "l" jumpfalse block.end.20485 clear add "ll" block.end.20485: testis "C" jumpfalse block.end.20518 clear add "nochars" block.end.20518: testis "L" jumpfalse block.end.20551 clear add "nolines" block.end.20551: testis "^" jumpfalse block.end.20583 clear add "escape" block.end.20583: testis "v" jumpfalse block.end.20617 clear add "unescape" block.end.20617: testis "z" jumpfalse block.end.20648 clear add "delim" block.end.20648: testis "S" jumpfalse block.end.20679 clear add "state" block.end.20679: testis "f" jumpfalse block.end.20710 clear add "write" block.end.20710: testis "r" jumpfalse block.end.20740 clear add "read" block.end.20740: testis "R" jumpfalse block.end.20771 clear add "until" block.end.20771: testis "T" jumpfalse block.end.20806 clear add "untiltape" block.end.20806: testis "w" jumpfalse block.end.20838 clear add "while" block.end.20838: testis "W" jumpfalse block.end.20872 clear add "whilenot" block.end.20872: testis "o" jumpfalse block.end.20901 clear add "nop" block.end.20901: # we can probably omit tests and jumps since they are not # designed to be used in scripts (only assembled parse programs). # "b" { clear; add "jump"; } # "j" { clear; add "jumptrue"; } # "J" { clear; add "jumpfalse"; } # "=" { clear; add "testis"; } # "?" { clear; add "testclass"; } # "b" { clear; add "testbegins"; } # "B" { clear; add "testends"; } # "E" { clear; add "testeof"; } # "*" { clear; add "testtape"; } # testis "n" jumpfalse block.end.21381 clear add "count" block.end.21381: testis "+" jumpfalse block.end.21409 clear add "a+" block.end.21409: testis "-" jumpfalse block.end.21437 clear add "a-" block.end.21437: testis "0" jumpfalse block.end.21467 clear add "zero" block.end.21467: testis "c" jumpfalse block.end.21499 clear add "cc" block.end.21499: testis "chars" jumpfalse block.end.21531 clear add "cc" block.end.21531: testis "l" jumpfalse block.end.21563 clear add "ll" block.end.21563: testis "lines" jumpfalse block.end.21595 clear add "ll" block.end.21595: testis "^" jumpfalse block.end.21627 clear add "escape" block.end.21627: testis "v" jumpfalse block.end.21661 clear add "unescape" block.end.21661: testis "z" jumpfalse block.end.21692 clear add "delim" block.end.21692: testis "S" jumpfalse block.end.21723 clear add "state" block.end.21723: testis "q" jumpfalse block.end.21753 clear add "quit" block.end.21753: testis "Q" jumpfalse block.end.21783 clear add "bail" block.end.21783: testis "s" jumpfalse block.end.21814 clear add "write" block.end.21814: testis "o" jumpfalse block.end.21843 clear add "nop" block.end.21843: testis "rs" jumpfalse block.end.21877 clear add "restart" block.end.21877: testis "rp" jumpfalse block.end.21911 clear add "reparse" block.end.21911: # some extra syntax for testeof and testtape testis "" jumptrue 4 testis "" jumptrue 2 jump block.end.22022 put clear add "eof*" push jump parse block.end.22022: testis "<==>" jumpfalse block.end.22080 put clear add "tapetest*" push jump parse block.end.22080: # "nochars", "nolines" { # put; clear; # add "The command '"; get; add "' (near line "; ll; add ")\n"; # add "has not been implemented, but needs to be. \n"; # print; clear; quit; # } # testis "add" jumptrue 102 testis "clip" jumptrue 100 testis "clop" jumptrue 98 testis "replace" jumptrue 96 testis "clear" jumptrue 94 testis "upper" jumptrue 92 testis "lower" jumptrue 90 testis "cap" jumptrue 88 testis "print" jumptrue 86 testis "pop" jumptrue 84 testis "push" jumptrue 82 testis "unstack" jumptrue 80 testis "stack" jumptrue 78 testis "put" jumptrue 76 testis "get" jumptrue 74 testis "swap" jumptrue 72 testis "++" jumptrue 70 testis "--" jumptrue 68 testis "mark" jumptrue 66 testis "go" jumptrue 64 testis "read" jumptrue 62 testis "until" jumptrue 60 testis "while" jumptrue 58 testis "whilenot" jumptrue 56 testis "jump" jumptrue 54 testis "jumptrue" jumptrue 52 testis "jumpfalse" jumptrue 50 testis "testis" jumptrue 48 testis "testclass" jumptrue 46 testis "testbegins" jumptrue 44 testis "testends" jumptrue 42 testis "testeof" jumptrue 40 testis "testtape" jumptrue 38 testis "count" jumptrue 36 testis "a+" jumptrue 34 testis "a-" jumptrue 32 testis "zero" jumptrue 30 testis "cc" jumptrue 28 testis "ll" jumptrue 26 testis "nochars" jumptrue 24 testis "nolines" jumptrue 22 testis "escape" jumptrue 20 testis "unescape" jumptrue 18 testis "delim" jumptrue 16 testis "state" jumptrue 14 testis "quit" jumptrue 12 testis "bail" jumptrue 10 testis "write" jumptrue 8 testis "nop" jumptrue 6 testis "reparse" jumptrue 4 testis "restart" jumptrue 2 jump block.end.22808 put clear add "word*" push jump parse block.end.22808: #------------ # the .reparse command and "parse label" is a simple way to # make sure that all shift-reductions occur. It should be used inside # a block test, so as not to create an infinite loop. testis "parse>" jumpfalse block.end.23124 clear add "parse:" put clear add "command*" push jump parse block.end.23124: # -------------------- # try to implement begin-blocks, which are only executed # once, at the beginning of the script (similar to awk's BEGIN {} rules) testis "begin" jumpfalse block.end.23340 put add "*" push jump parse block.end.23340: put add "Pep syntax error: unknown command '" get add "' \n" add "on line " ll add " (or character " cc add ")" add "of input (file or stream). \n" print clear quit # ---------------------------------- # PARSING PHASE: # the lexing phase finishes here, and below is the # parse/compile phase of the script. Here we pop tokens # off the stack and check for sequences of tokens eg word*semicolon* # If we find a valid series of tokens, we "shift-reduce" or "resolve" # the token series eg word*semicolon* --> command* # At the same time, we manipulate (transform) the attributes on the # tape, as required. So Tape=|pop|;| becomes |\npop| where the # bars | indicate tape cells. (2 tapes cells are merged into 1). # Each time the stack is reduced, the tape must also be reduced # parse: #------------------------------------- # 2 tokens #------------------------------------- pop pop # All of the below are currently errors, but may not # be in the future if we expand the syntax of the parse # language. Also consider: # begintext* endtext* quoteset* notclass*, !* ,* ;* B* E* # It is nice to trap the errors here because we can emit some # hopefully not-very-cryptic error messages with a line number. # Otherwise the script writer has to debug with # pep -a asm.pp scriptfile -I testis "word*word*" jumptrue 50 testis "word*}*" jumptrue 48 testis "word*begintext*" jumptrue 46 testis "word*endtext*" jumptrue 44 testis "word*!*" jumptrue 42 testis "word*,*" jumptrue 40 testis "quote*word*" jumptrue 38 testis "quote*class*" jumptrue 36 testis "quote*state*" jumptrue 34 testis "quote*}*" jumptrue 32 testis "quote*begintext*" jumptrue 30 testis "quote*endtext*" jumptrue 28 testis "class*word*" jumptrue 26 testis "class*quote*" jumptrue 24 testis "class*class*" jumptrue 22 testis "class*state*" jumptrue 20 testis "class*}*" jumptrue 18 testis "class*begintext*" jumptrue 16 testis "class*endtext*" jumptrue 14 testis "class*!*" jumptrue 12 testis "notclass*word*" jumptrue 10 testis "notclass*quote*" jumptrue 8 testis "notclass*class*" jumptrue 6 testis "notclass*state*" jumptrue 4 testis "notclass*}*" jumptrue 2 jump block.end.25290 push push add "error near line " ll add " (char " cc add ")" add " of script (missing semicolon/brace/unescaped quote??) \n" print clear quit block.end.25290: testis "{*;*" jumptrue 6 testis ";*;*" jumptrue 4 testis "}*;*" jumptrue 2 jump block.end.25479 push push add "error near line " ll add " (char " cc add ")" add " of script: misplaced semi-colon? ; \n" print clear quit block.end.25479: # comma errors. testis ",*;*" jumptrue 6 testis ",*{*" jumptrue 4 testis ",*}*" jumptrue 2 jump block.end.25679 push push add "error near line " ll add " (char " cc add ")" add " of script: misplaced comma? ; \n" print clear quit block.end.25679: testis ",*{*" jumpfalse block.end.25852 push push add "Pep: error near line " ll add " (char " cc add ")" add " of script: extra comma in list? \n" print clear quit block.end.25852: testis "command*;*" jumptrue 4 testis "commandset*;*" jumptrue 2 jump block.end.26044 push push add "Pep: error near line " ll add " (char " cc add ")" add " of script: extra semi-colon? \n" print clear quit block.end.26044: testis "!*!*" jumpfalse block.end.26310 push push add "Pep: error near line " ll add " (char " cc add ")" add " of script: \n double negation '!!' is not implemented \n" add " and probably won't be, because what would be the point? \n" print clear quit block.end.26310: testis "!*{*" jumptrue 4 testis "!*;*" jumptrue 2 jump block.end.26624 push push add "Pep: error near line " ll add " (char " cc add ")" add " of script: misplaced negation operator (!)? \n" add " The negation operator precedes tests, for example: \n" add " !B'abc'{ ... } or !(eof),!'abc'{ ... } \n" print clear quit block.end.26624: testis ",*command*" jumpfalse block.end.26794 push push add "error near line " ll add " (char " cc add ")" add " of script: misplaced comma? \n" print clear quit block.end.26794: testis "!*command*" jumpfalse block.end.26993 push push add "error near line " ll add " (at char " cc add ") \n" add " The negation operator (!) cannot precede a command \n" print clear quit block.end.26993: testis ";*{*" jumptrue 6 testis "command*{*" jumptrue 4 testis "commandset*{*" jumptrue 2 jump block.end.27196 push push add "error near line " ll add " (char " cc add ")" add " of script: no test for brace block? \n" print clear quit block.end.27196: testis "{*}*" jumpfalse block.end.27327 push push add "error near line " ll add " of script: empty braces {}. \n" print clear quit block.end.27327: testis "B*class*" jumptrue 4 testis "E*class*" jumptrue 2 jump block.end.27555 push push add "error near line " ll add " of script:\n classes ([a-z], [:space:] etc). \n" add " cannot use the 'begin' or 'end' modifiers (B/E) \n" print clear quit block.end.27555: testis "}*command*" jumpfalse block.end.27702 push push add "error near line " ll add " of script: extra closing brace '}' ?. \n" print clear quit block.end.27702: testis "comment*{*" jumpfalse block.end.27891 push push add "error near line " ll add " of script: comments cannot occur between \n" add " a test and a brace ({). \n" print clear quit block.end.27891: #------------ # the .restart command just jumps to the start: label # (which is usually followed by a "read" command) # but '.' is also the AND concatenator, which seems ambiguous, # but the parsing works. testis ".*word*" jumpfalse block.end.28585 clear ++ get -- testis "restart" jumpfalse block.end.28263 clear add "jump start" put clear add "command*" push jump parse block.end.28263: testis "reparse" jumpfalse block.end.28378 clear add "jump parse" put clear add "command*" push jump parse block.end.28378: push push add "error near line " ll add " (char " cc add ")" add " of script: \n" add " misplaced dot '.' (use for AND logic or in .reparse/.restart \n" print clear quit block.end.28585: #----------------------------------------- # compiling comments so as to transfer them to the compiled # file. # implement these rules to conserve comments testis "comment*command*" jumptrue 6 testis "command*comment*" jumptrue 4 testis "commandset*comment*" jumptrue 2 jump block.end.28907 clear get add "\n" ++ get -- put clear add "command*" push jump parse block.end.28907: testis "comment*comment*" jumpfalse block.end.29021 clear get add "\n" ++ get -- put clear add "comment*" push jump parse block.end.29021: # ----------------------- # negated tokens. # This is a new more elegant way to negate a whole set of # tests (tokens) where the negation logic is stored on the # stack, not in the current tape cell. We just add "not" to # the stack token. # eg: ![:alpha:] ![a-z] ![abcd] !"abc" !B"abc" !E"xyz" # This format is used to indicate a negative test for # a brace block. eg: ![aeiou] { add "< not a vowel"; print; clear; } testis "!*quote*" jumptrue 12 testis "!*class*" jumptrue 10 testis "!*begintext*" jumptrue 8 testis "!*endtext*" jumptrue 6 testis "!*eof*" jumptrue 4 testis "!*tapetest*" jumptrue 2 jump block.end.29764 # a simplification: just replace the token name with its # negative. replace "!*" "not" push # now get the token-value # added an extra ++ here. get -- put ++ clear jump parse block.end.29764: #----------------------------------------- # format: E"text" or E'text' # This format is used to indicate a "workspace-ends-with" text before # a brace block. testis "E*quote*" jumpfalse block.end.30036 clear add "endtext*" push get -- put ++ clear jump parse block.end.30036: #----------------------------------------- # format: B"sometext" or B'sometext' # A 'B' preceding some quoted text is used to indicate a # 'workspace-begins-with' test, before a brace block. testis "B*quote*" jumpfalse block.end.30347 clear add "begintext*" push get -- put ++ clear jump parse block.end.30347: #-------------------------------------------- # ebnf: command := word, ';' ; # formats: "pop; push; clear; print; " etc # all commands need to end with a semi-colon except for # .reparse and .restart testis "word*;*" jumpfalse block.end.31103 clear # check if command requires parameter get testis "add" jumptrue 18 testis "while" jumptrue 16 testis "whilenot" jumptrue 14 testis "mark" jumptrue 12 testis "go" jumptrue 10 testis "escape" jumptrue 8 testis "unescape" jumptrue 6 testis "delim" jumptrue 4 testis "replace" jumptrue 2 jump block.end.30899 put clear add "Pep: '" get add "'" add " << command needs an argument, on line " ll add " of script.\n" print clear quit block.end.30899: # the no-argument version of until testis "until" jumpfalse block.end.30973 add "tape" put block.end.30973: clear add "command*" # no need to format tape cells because current cell contains word push jump parse block.end.31103: #----------------------------------------- # ebnf: commandset := command , command ; testis "command*command*" jumptrue 4 testis "commandset*command*" jumptrue 2 jump block.end.31427 clear add "commandset*" push # format the tape attributes. Add the next command on a newline -- get add "\n" ++ get -- put ++ clear jump parse block.end.31427: #------------------- # here we begin to parse "test*" and "ortestset*" and "andtestset*" # #------------------- # eg: B"abc" {} or E"xyz" {} testis "begintext*{*" jumptrue 12 testis "endtext*{*" jumptrue 10 testis "quote*{*" jumptrue 8 testis "class*{*" jumptrue 6 testis "eof*{*" jumptrue 4 testis "tapetest*{*" jumptrue 2 jump block.end.32450 # set accumulator == 0 zero testbegins "begin" jumpfalse block.end.31743 clear add "testbegins " block.end.31743: testbegins "end" jumpfalse block.end.31782 clear add "testends " block.end.31782: testbegins "quote" jumpfalse block.end.31821 clear add "testis " block.end.31821: testbegins "class" jumpfalse block.end.31863 clear add "testclass " block.end.31863: # clear the tapecell for testeof and testtape because # they take no arguments. testbegins "eof" jumpfalse block.end.31995 clear put add "testeof " block.end.31995: testbegins "tapetest" jumpfalse block.end.32044 clear put add "testtape " block.end.32044: get add "\n" add "jumptrue 2 \n" # this extra jump has utility when we parse ortestsets and # andtestsets. add "jump block.end." # the final jumpfalse + target will be added when # "test*{*commandset*}*" is parsed, or when # "ortestset*{*commandset*}*" # "andtestset*{*commandset*}*" put a+ a+ a+ a+ clear add "test*{*" push push jump parse block.end.32450: #------------------- # negated tests # eg: !B"xyz {} # !E"xyz" {} # !"abc" {} # ![a-z] {} testis "notbegintext*{*" jumptrue 12 testis "notendtext*{*" jumptrue 10 testis "notquote*{*" jumptrue 8 testis "notclass*{*" jumptrue 6 testis "noteof*{*" jumptrue 4 testis "nottapetest*{*" jumptrue 2 jump block.end.33419 # set accumulator == 0 zero testbegins "notbegin" jumpfalse block.end.32749 clear add "testbegins " block.end.32749: testbegins "notend" jumpfalse block.end.32791 clear add "testends " block.end.32791: testbegins "notquote" jumpfalse block.end.32833 clear add "testis " block.end.32833: testbegins "notclass" jumpfalse block.end.32878 clear add "testclass " block.end.32878: # clear the tapecell for testeof and testtape because # they take no arguments. testbegins "noteof" jumpfalse block.end.33013 clear put add "testeof " block.end.33013: testbegins "nottapetest" jumpfalse block.end.33065 clear put add "testtape " block.end.33065: get add "\n" add "jumpfalse 2 \n" # this extra jump has utility when we parse ortestsets and # andtestsets. add "jump block.end." # the final jumpfalse + target will be added later # use the accumulator to store the incremented jump target put a+ a+ a+ a+ clear add "test*{*" push push jump parse block.end.33419: #------------------- # 3 tokens #------------------- pop #----------------------------- # some 3 token errors!!! # there are many other of these errors but I am not going # to write them all. testis "{*begintext*;*" jumptrue 6 testis "{*endtext*;*" jumptrue 4 testis "{*class*;*" jumptrue 2 jump block.end.33845 push push push add "error near line " ll add " (char " cc add ")" add " of script (misplaced semicolon?) \n" print clear quit block.end.33845: testis "{*quote*;*" jumptrue 6 testis "commandset*quote*;*" jumptrue 4 testis "command*quote*;*" jumptrue 2 jump block.end.34077 push push push add "[error] near line " ll add " (char " cc add ")" add " of script (quoted text without a command?) \n" print clear quit block.end.34077: # to simplify subsequent tests, transmogrify a single command # to a commandset (multiple commands). testis "{*command*}*" jumpfalse block.end.34273 clear add "{*commandset*}*" push push push jump parse block.end.34273: # rule #',' ortestset ::= ',' test '{' # trigger a transmogrification from test to ortestset token # and # '.' andtestset ::= '.' test '{' testis ",*test*{*" jumpfalse block.end.34510 clear add ",*ortestset*{*" push push push jump parse block.end.34510: # trigger a transmogrification from "test" to "andtest" by # looking backwards in the stack testis ".*test*{*" jumpfalse block.end.34747 # the jump counter is 1 too high for AND tests a- clear add ".*andtestset*{*" push push push jump parse block.end.34747: # errors! mixing AND and OR concatenation testis ",*andtestset*{*" jumptrue 4 testis ".*ortestset*{*" jumptrue 2 jump block.end.35079 # push the tokens back to make debugging easier push push push add " error: mixing AND (.) and OR (,) concatenation in \n" add " in script near line " ll add " (character " cc add ") \n" print clear quit block.end.35079: #-------------------------------------------- # ebnf: command := keyword , quoted-text , ";" ; # format: add "text"; testis "word*quote*;*" jumpfalse block.end.36771 clear get testis "replace" jumpfalse block.end.35419 # error add "< command requires 2 parameters, not 1 \n" add "near line " ll add " of script. \n" print clear quit block.end.35419: testis "add" jumptrue 20 testis "until" jumptrue 18 testis "while" jumptrue 16 testis "whilenot" jumptrue 14 testis "escape" jumptrue 12 testis "mark" jumptrue 10 testis "go" jumptrue 8 testis "unescape" jumptrue 6 testis "delim" jumptrue 4 testis "write" jumptrue 2 jump block.end.36589 # check here or in error.pss for multiline quoted arguments # for "mark" "go" "until" etc because they are not allowed. clear add "command*" push # a command plus argument, eg add "this" -- get # allow multiline text in (only) the add command # we do this by turning a multiline "add" command into a # sequence of single line "add" commands (because that is what # the assembler format allows). Actually, I could just write # replace "\n" "\\n"; which should work but would be much less # readable in the assembled file. testis "add" jumpfalse block.end.36260 add " " ++ get replace "\n" "\\n\"\nadd \"" -- put ++ clear jump parse block.end.36260: # maybe it would be useful for the until command to # allow multiline as well testis "until" jumpfalse block.end.36483 add " " ++ get replace "\n" "\\n" -- put ++ clear jump parse block.end.36483: testis "write" jumpfalse block.end.36514 add "file" block.end.36514: add " " ++ get -- put ++ clear jump parse block.end.36589: # error, superfluous argument add ": command does not take an argument \n" add "near line " ll add " of script. \n" print #state quit block.end.36771: #---------------------------------- # format: "while [:alpha:] ;" or whilenot [a-z] ; testis "word*class*;*" jumpfalse block.end.37279 clear get testis "while" jumptrue 4 testis "whilenot" jumptrue 2 jump block.end.37129 clear add "command*" push # a command plus argument, eg while [a-z] -- get add " " ++ get -- put ++ clear jump parse block.end.37129: # error add " < command cannot have a class argument \n" add "line " ll add ": error in script \n" print clear quit block.end.37279: # ------------------------------- # 4 tokens # ------------------------------- pop #------------------------------------- # ebnf: command := replace , quote , quote , ";" ; # example: replace "and" "AND" ; testis "word*quote*quote*;*" jumpfalse block.end.37947 clear get testis "replace" jumpfalse block.end.37820 clear add "command*" push #--------------------------- # a command plus 2 arguments, eg replace "this" "that" -- get add " " ++ get add " " ++ get -- -- put ++ clear jump parse block.end.37820: add " << command does not take 2 quoted arguments. \n" add " on line " ll add " of script.\n" print quit block.end.37947: #------------------------------------- # format: begin { #* commands *# } # "begin" blocks which are only executed once (they # will are assembled before the "start:" label. They must come before # all other commands. # "begin*{*command*}*", testis "begin*{*commandset*}*" jumpfalse block.end.38331 clear ++ ++ get -- -- put clear add "beginblock*" push jump parse block.end.38331: # ------------- # parses and compiles concatenated tests # eg: 'a',B'b',E'c',[def],[:space:],[g-k] { ... testis "begintext*,*ortestset*{*" jumptrue 12 testis "endtext*,*ortestset*{*" jumptrue 10 testis "quote*,*ortestset*{*" jumptrue 8 testis "class*,*ortestset*{*" jumptrue 6 testis "eof*,*ortestset*{*" jumptrue 4 testis "tapetest*,*ortestset*{*" jumptrue 2 jump block.end.39255 testbegins "begin" jumpfalse block.end.38660 clear add "testbegins " block.end.38660: testbegins "end" jumpfalse block.end.38700 clear add "testends " block.end.38700: testbegins "quote" jumpfalse block.end.38740 clear add "testis " block.end.38740: testbegins "class" jumpfalse block.end.38783 clear add "testclass " block.end.38783: # clear the tapecell for testeof and testtape because # they take no arguments. testbegins "eof" jumpfalse block.end.38918 clear put add "testeof " block.end.38918: testbegins "tapetest" jumpfalse block.end.38968 clear put add "testtape " block.end.38968: get add "\n" add "jumptrue " count add "\n" ++ ++ get -- -- put clear # this works as long as we dont mix AND and OR concatenations # add "test*{*"; # need to change to this add "ortestset*{*" push push a+ a+ jump parse block.end.39255: # A collection of negated tests. testis "notbegintext*,*ortestset*{*" jumptrue 12 testis "notendtext*,*ortestset*{*" jumptrue 10 testis "notquote*,*ortestset*{*" jumptrue 8 testis "notclass*,*ortestset*{*" jumptrue 6 testis "noteof*,*ortestset*{*" jumptrue 4 testis "nottapetest*,*ortestset*{*" jumptrue 2 jump block.end.40052 testbegins "notbegin" jumpfalse block.end.39527 clear add "testbegins " block.end.39527: testbegins "notend" jumpfalse block.end.39570 clear add "testends " block.end.39570: testbegins "notquote" jumpfalse block.end.39613 clear add "testis " block.end.39613: testbegins "notclass" jumpfalse block.end.39659 clear add "testclass " block.end.39659: testbegins "noteof" jumpfalse block.end.39706 clear put add "testeof " block.end.39706: testbegins "nottapetest" jumpfalse block.end.39759 clear put add "testtape " block.end.39759: get add "\n" add "jumpfalse " count add "\n" ++ ++ get -- -- put clear # this works as long as we dont mix AND and OR concatenations add "ortestset*{*" # need to change to this # add "ortestset*{*"; push push a+ a+ jump parse block.end.40052: # this works as long as we dont mix AND and OR concatenations # ------------- # AND logic # parses and compiles concatenated AND tests # eg: 'a',B'b',E'c',[def],[:space:],[g-k] { ... # it is possible to elide this block with the negated block # for compactness but maybe readability is not as good. testis "begintext*.*andtestset*{*" jumptrue 12 testis "endtext*.*andtestset*{*" jumptrue 10 testis "quote*.*andtestset*{*" jumptrue 8 testis "class*.*andtestset*{*" jumptrue 6 testis "eof*.*andtestset*{*" jumptrue 4 testis "tapetest*.*andtestset*{*" jumptrue 2 jump block.end.40982 testbegins "begin" jumpfalse block.end.40596 clear add "testbegins " block.end.40596: testbegins "end" jumpfalse block.end.40636 clear add "testends " block.end.40636: testbegins "quote" jumpfalse block.end.40676 clear add "testis " block.end.40676: testbegins "class" jumpfalse block.end.40719 clear add "testclass " block.end.40719: testbegins "eof" jumpfalse block.end.40763 clear put add "testeof " block.end.40763: testbegins "tapetest" jumpfalse block.end.40813 clear put add "testtape " block.end.40813: get add "\n" add "jumpfalse " count add "\n" ++ ++ get -- -- put clear add "andtestset*{*" push push a+ a+ jump parse block.end.40982: # eg # negated tests concatenated with AND logic (.). The # negated tests can be chained with non negated tests. # eg: B'http' . !E'.txt' { ... } testis "notbegintext*.*andtestset*{*" jumptrue 12 testis "notendtext*.*andtestset*{*" jumptrue 10 testis "notquote*.*andtestset*{*" jumptrue 8 testis "notclass*.*andtestset*{*" jumptrue 6 testis "noteof*.*andtestset*{*" jumptrue 4 testis "nottapetest*.*andtestset*{*" jumptrue 2 jump block.end.41783 testbegins "notbegin" jumpfalse block.end.41383 clear add "testbegins " block.end.41383: testbegins "notend" jumpfalse block.end.41426 clear add "testends " block.end.41426: testbegins "notquote" jumpfalse block.end.41469 clear add "testis " block.end.41469: testbegins "notclass" jumpfalse block.end.41515 clear add "testclass " block.end.41515: testbegins "noteof" jumpfalse block.end.41562 clear put add "testeof " block.end.41562: testbegins "nottapetest" jumpfalse block.end.41615 clear put add "testtape " block.end.41615: get add "\n" add "jumptrue " count add "\n" ++ ++ get -- -- put clear add "andtestset*{*" push push a+ a+ jump parse block.end.41783: #------------------------------------- # we should not have to check for the {*command*}* pattern # because that has already been transformed to {*commandset*}* testis "test*{*commandset*}*" jumptrue 6 testis "andtestset*{*commandset*}*" jumptrue 4 testis "ortestset*{*commandset*}*" jumptrue 2 jump block.end.42854 # indent the assembled code for readability testbegins "test*{*" jumpfalse block.end.42404 clear # get rid of unnecessary jump but only in "test" cases get # for positive tests (eg [a-z] {...}) replace "jumptrue 2 \njump" "jumpfalse" put # for negative tests (eg ![a-z] {...}) replace "jumpfalse 2 \njump" "jumptrue" put block.end.42404: clear ++ ++ add " " get replace "\n" "\n " put -- -- clear get # the final jump (to the closing brace) has already been # coded in the "test*{*" rule or the other rules. # we just need to add the label number with "cc" cc add "\n" ++ ++ get add "\nblock.end." cc add ":" -- -- put clear add "command*" push # always reparse/compile jump parse block.end.42854: # ------------- # multi-token end-of-stream errors # not a comprehensive list of errors... testeof jumpfalse block.end.43630 testends "begintext*" jumptrue 10 testends "endtext*" jumptrue 8 testends "test*" jumptrue 6 testends "ortestset*" jumptrue 4 testends "andtestset*" jumptrue 2 jump block.end.43161 add " Error near end of script at line " ll add ". Test with no brace block? \n" print clear quit block.end.43161: testends "quote*" jumptrue 6 testends "class*" jumptrue 4 testends "word*" jumptrue 2 jump block.end.43373 put clear add "Error end of script! (line " ll add ") missing semi-colon? \n" add "Parse stack: " get add "\n" print clear quit block.end.43373: testends "{*" jumptrue 16 testends "}*" jumptrue 14 testends ";*" jumptrue 12 testends ",*" jumptrue 10 testends ".*" jumptrue 8 testends "!*" jumptrue 6 testends "B*" jumptrue 4 testends "E*" jumptrue 2 jump block.end.43626 put clear add "Error: misplaced terminal character at end of script! (line " ll add "). \n" add "Parse stack: " get add "\n" print clear quit block.end.43626: block.end.43630: # put the 4 (or less) tokens back on the stack push push push push testeof jumpfalse block.end.45671 #add "end of script!! \n" print clear #--------------------- # check if the script correctly parsed (there should only # be one token on the stack, namely "commandset*" or "command*" pop pop testis "commandset*" jumptrue 4 testis "command*" jumptrue 2 jump block.end.44523 push -- add "# Assembled with the script 'compile.pss' \n" add "start:\n" get # an extra space because of a bug in compile() add "\njump start \n" # put a copy of the final compilation into the tapecell # so it can be inspected interactively. put # remove this print from asm.pp after generating a new asm.pp # with pep -f compile.pss compile.pss > asm.new.pp; cp asm.new.pp asm.pp print # remove! # save the compiled script to 'sav.pp' write clear quit block.end.44523: testis "beginblock*commandset*" jumptrue 4 testis "beginblock*command*" jumptrue 2 jump block.end.45163 clear add "# Assembled with the script 'compile.pss' \n" get add "\n" ++ add "start:\n" get # an extra space because of a bug in compile() add "\njump start \n" # put a copy of the final compilation into the tapecell # so it can be inspected interactively. put # remove this 'print' from asm.pp after generating a new asm.pp # with pep -f compile.pss compile.pss > asm.new.pp; cp asm.new.pp asm.pp print # remove! # also save the compiled script to 'sav.pp' write clear quit block.end.45163: push push # state clear add "After compiling with 'compile.pss' (at EOF): \n " add " parse error in input script, check syntax: \n " add " To debug script try the -I switch with \n " add " >> pep -If script -i 'some input' \n " add " or to debug the compilation process try: \n " add " >> pep -Ia asm.pp script' \n " print clear # clear sav.pp because script could not be compiled write # bail means exit with error bail block.end.45671: # not eof # there is an implicit .restart command here (jump start) jump start