# 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
#   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.
#
#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 gh.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 compilable.c.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; } 
#
#  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/gh.c 
#     the current implementation of the machine interpreter and debugger. 
#   object/*.c 
#     the virtual machine and components 
#   compile.java.pss
#     attempts to compile scripts to java using a machine object in
#     object.java/
#   compile.js.pss
#     attempts to compile scripts to javascript using a machine object in
#     object.javascript/ and nodejs
#   compilable.c.pss 
#     compiles a script to c code (but is out of date as of 13 mar 2020)
#   asm.handcode.pp
#     a handcoded "assembly" compiler of the parse script language for 
#     a previous version of the script language.
#   object/machine.methods.c
#     a set of functions to perform instructions on the parse machine.
#    
#USAGE
#
#   This script can be 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. I would like to preserve comments in the
#   output. 
#   
#   We can also do the strange operation
#     >> pep -f compile.pss compile.pss
#   which actually creates an 'assembler' version of itself in 'sav.pp'
#   which should then be suitable for use as an 'asm.pp' substitute.
#   This is quite tricky to think about since it is so self-referential.
#
#   But this is analogous to the equally strange operation
#     >> pep -f compilable.c.pss compilable.c.pss
#   which generates a compilable c language program of the compilable 
#   script.
#
#   It may be possible to compile this script into a stand-alone
#   executable with: (untested)
#   ----
#      pep -f compilable.c.pss compile.pss > compile.c
#      gcc -o compile.exec -Lobject -lmachine -Iobject
#   ,,,,
#
#   Also, it may be more useful for this script to print out its
#   output rather than writing it to file.
#
#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
#
#BUGS
#   
#  * doesnt catch B[abc] or E[a-z] type errors in scripts. Also 
#    doesnt catch "r;r;d" type errors.
#
#  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 not 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
#
#  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.
#
#  Allow multiline arguments with the "add" 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
#    compile.java.pss compile.tcl.pss etc.
#
#
#HISTORY
#    
#  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 <eof> <EOF> 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 "testis"
#    >> /usr/local/bin/pp -f compile.pss -i 'r;!"b",!"a"{nop;}'
#
#  23 august 2019
#    
#    adding begintests and endtests to the quoteset logic. But
#    need to juggle the combinations. Also could add classes 
#    and notclasses. more or less working. But should actually 
#    changing 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 quotesets tokens which produce
#    nifty but very poor code. need 'tapereplace' command for this.
#    
#  6 august 2019
#
#    would be handy to have multiline quotes. should be 
#    easy to include. In fact they probably should already work, dont
#    know why not...
#
#  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
#--------------
testclass [:space:]
jumpfalse block.end.12954
  clear
  jump parse
block.end.12954:
#---------------
# 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.13316
  put
  add "*"
  push
  jump parse
block.end.13316:
#---------------
# format: "text"
testis "\""
jumpfalse block.end.13669
  # save the line number in case there is no terminating
  # quote.
  clear
  ll
  put
  clear
  add "\""
  until "\""
  testends "\""
  jumptrue block.end.13611
    clear
    add "Unterminated quote (\") starting at line "
    get
    add " !\n"
    print
    quit
  block.end.13611:
  put
  clear
  add "quote*"
  push
  jump parse
block.end.13669:
#---------------
# format: 'text', single quotes are converted to double quotes
# but we must escape embedded double quotes.
testis "'"
jumpfalse block.end.14169
  # save the line number in case there is no terminating
  # quote.
  clear
  ll
  put
  clear
  until "'"
  testends "'"
  jumptrue block.end.14044
    clear
    add "Unterminated quote (\") starting at line "
    get
    add "!\n"
    print
    quit
  block.end.14044:
  clip
  escape "\""
  put
  clear
  add "\""
  get
  add "\""
  put
  clear
  add "quote*"
  push
  jump parse
block.end.14169:
#---------------
# formats: [:space:] [a-z] [abcd] [:alpha:] etc 
testis "["
jumpfalse block.end.14317
  until "]"
  put
  clear
  add "class*"
  push
  jump parse
block.end.14317:
#---------------
# formats: (eof) (==) etc. I may change this syntax to just
# EOF and ==
testis "("
jumpfalse block.end.14826
  clear
  until ")"
  clip
  put
  testis "eof"
  jumptrue 4
  testis "EOF"
  jumptrue 2 
  jump block.end.14511
    clear
    add "eof*"
    push
    jump parse
  block.end.14511:
  testis "=="
  jumpfalse block.end.14564
    clear
    add "tapetest*"
    push
    jump parse
  block.end.14564:
  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.14826:
#---------------
# multiline and single line comments, eg #... and #* ... *#
testis "#"
jumpfalse block.end.15875
  clear
  read
  testis "\n"
  jumpfalse block.end.14962
    clear
    jump parse
  block.end.14962:
  # checking for multiline comments of the form "#* \n\n\n *#"
  # these are just ignored at the moment (deleted) 
  testis "*"
  jumpfalse block.end.15721
    # save the line number for possible error message later
    clear
    ll
    put
    clear
    until "*#"
    testends "*#"
    jumpfalse block.end.15466
      # 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.15466:
    # 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.15721:
  # single line comments. some will get lost.
  put
  clear
  add "#"
  get
  until "\n"
  clip
  put
  clear
  add "comment*"
  push
  jump parse
block.end.15875:
#----------------------------------
# parse command words (and abbreviations)
# legal characters for keywords (commands)
testclass [abcdefghijklmnopqrstuvwxyzBEKGPRUWS+-<>0^]
jumptrue block.end.16256
  # 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.16256:
# 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.16840
  clear
  add "ll"
block.end.16840:
testis "chars"
jumpfalse block.end.16872
  clear
  add "cc"
block.end.16872:
# one letter command abbreviations
testis "a"
jumpfalse block.end.16939
  clear
  add "add"
block.end.16939:
testis "k"
jumpfalse block.end.16969
  clear
  add "clip"
block.end.16969:
testis "K"
jumpfalse block.end.16999
  clear
  add "clop"
block.end.16999:
testis "D"
jumpfalse block.end.17032
  clear
  add "replace"
block.end.17032:
testis "d"
jumpfalse block.end.17063
  clear
  add "clear"
block.end.17063:
testis "t"
jumpfalse block.end.17094
  clear
  add "print"
block.end.17094:
testis "p"
jumpfalse block.end.17123
  clear
  add "pop"
block.end.17123:
testis "P"
jumpfalse block.end.17153
  clear
  add "push"
block.end.17153:
testis "u"
jumpfalse block.end.17186
  clear
  add "unstack"
block.end.17186:
testis "U"
jumpfalse block.end.17217
  clear
  add "stack"
block.end.17217:
testis "G"
jumpfalse block.end.17246
  clear
  add "put"
block.end.17246:
testis "g"
jumpfalse block.end.17275
  clear
  add "get"
block.end.17275:
testis "x"
jumpfalse block.end.17305
  clear
  add "swap"
block.end.17305:
testis ">"
jumpfalse block.end.17333
  clear
  add "++"
block.end.17333:
testis "<"
jumpfalse block.end.17361
  clear
  add "--"
block.end.17361:
testis "m"
jumpfalse block.end.17391
  clear
  add "mark"
block.end.17391:
testis "M"
jumpfalse block.end.17419
  clear
  add "go"
block.end.17419:
testis "r"
jumpfalse block.end.17449
  clear
  add "read"
block.end.17449:
testis "R"
jumpfalse block.end.17480
  clear
  add "until"
block.end.17480:
testis "w"
jumpfalse block.end.17511
  clear
  add "while"
block.end.17511:
testis "W"
jumpfalse block.end.17545
  clear
  add "whilenot"
block.end.17545:
# 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.18023
  clear
  add "count"
block.end.18023:
testis "+"
jumpfalse block.end.18051
  clear
  add "a+"
block.end.18051:
testis "-"
jumpfalse block.end.18079
  clear
  add "a-"
block.end.18079:
testis "0"
jumpfalse block.end.18109
  clear
  add "zero"
block.end.18109:
testis "c"
jumpfalse block.end.18141
  clear
  add "cc"
block.end.18141:
testis "chars"
jumpfalse block.end.18173
  clear
  add "cc"
block.end.18173:
testis "l"
jumpfalse block.end.18205
  clear
  add "ll"
block.end.18205:
testis "lines"
jumpfalse block.end.18237
  clear
  add "ll"
block.end.18237:
testis "^"
jumpfalse block.end.18269
  clear
  add "escape"
block.end.18269:
testis "v"
jumpfalse block.end.18303
  clear
  add "unescape"
block.end.18303:
testis "z"
jumpfalse block.end.18334
  clear
  add "delim"
block.end.18334:
testis "S"
jumpfalse block.end.18365
  clear
  add "state"
block.end.18365:
testis "q"
jumpfalse block.end.18395
  clear
  add "quit"
block.end.18395:
testis "Q"
jumpfalse block.end.18425
  clear
  add "bail"
block.end.18425:
testis "s"
jumpfalse block.end.18456
  clear
  add "write"
block.end.18456:
testis "o"
jumpfalse block.end.18485
  clear
  add "nop"
block.end.18485:
testis "rs"
jumpfalse block.end.18519
  clear
  add "restart"
block.end.18519:
testis "rp"
jumpfalse block.end.18553
  clear
  add "reparse"
block.end.18553:
# some extra syntax for testeof and testtape
testis "<eof>"
jumptrue 4
testis "<EOF>"
jumptrue 2 
jump block.end.18664
  put
  clear
  add "eof*"
  push
  jump parse
block.end.18664:
testis "<==>"
jumpfalse block.end.18722
  put
  clear
  add "tapetest*"
  push
  jump parse
block.end.18722:

#   "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.19450
  put
  clear
  add "word*"
  push
  jump parse
block.end.19450:
#------------ 
# 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.19766
  clear
  add "parse:"
  put
  clear
  add "command*"
  push
  jump parse
block.end.19766:
# --------------------
# 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.19982
  put
  add "*"
  push
  jump parse
block.end.19982:
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.21909
  push
  push
  add "error near line "
  ll
  add " (char "
  cc
  add ")"
  add " of script (missing semicolon?) \n"
  print
  clear
  quit
block.end.21909:
testis "{*;*"
jumptrue 6
testis ";*;*"
jumptrue 4
testis "}*;*"
jumptrue 2 
jump block.end.22098
  push
  push
  add "error near line "
  ll
  add " (char "
  cc
  add ")"
  add " of script: misplaced semi-colon? ; \n"
  print
  clear
  quit
block.end.22098:
# comma errors.
testis ",*;*"
jumptrue 6
testis ",*{*"
jumptrue 4
testis ",*}*"
jumptrue 2 
jump block.end.22298
  push
  push
  add "error near line "
  ll
  add " (char "
  cc
  add ")"
  add " of script: misplaced comma? ; \n"
  print
  clear
  quit
block.end.22298:
testis ",*{*"
jumpfalse block.end.22471
  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.22471:
testis "command*;*"
jumptrue 4
testis "commandset*;*"
jumptrue 2 
jump block.end.22663
  push
  push
  add "Pep: error near line "
  ll
  add " (char "
  cc
  add ")"
  add " of script: extra semi-colon? \n"
  print
  clear
  quit
block.end.22663:
testis "!*!*"
jumpfalse block.end.22929
  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.22929:
testis "!*{*"
jumptrue 4
testis "!*;*"
jumptrue 2 
jump block.end.23243
  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.23243:
testis ",*command*"
jumpfalse block.end.23413
  push
  push
  add "error near line "
  ll
  add " (char "
  cc
  add ")"
  add " of script: misplaced comma? \n"
  print
  clear
  quit
block.end.23413:
testis "!*command*"
jumpfalse block.end.23612
  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.23612:
testis ";*{*"
jumptrue 6
testis "command*{*"
jumptrue 4
testis "commandset*{*"
jumptrue 2 
jump block.end.23815
  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.23815:
testis "{*}*"
jumpfalse block.end.23946
  push
  push
  add "error near line "
  ll
  add " of script: empty braces {}. \n"
  print
  clear
  quit
block.end.23946:
testis "B*class*"
jumptrue 4
testis "E*class*"
jumptrue 2 
jump block.end.24174
  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.24174:
testis "}*command*"
jumpfalse block.end.24321
  push
  push
  add "error near line "
  ll
  add " of script: extra closing brace '}' ?. \n"
  print
  clear
  quit
block.end.24321:
testis "comment*{*"
jumpfalse block.end.24510
  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.24510:
#------------ 
# 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.25204
  clear
  ++
  get
  --
  testis "restart"
  jumpfalse block.end.24882
    clear
    add "jump start"
    put
    clear
    add "command*"
    push
    jump parse
  block.end.24882:
  testis "reparse"
  jumpfalse block.end.24997
    clear
    add "jump parse"
    put
    clear
    add "command*"
    push
    jump parse
  block.end.24997:
  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.25204:
#-----------------------------------------
# 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.25526
  clear
  get
  add "\n"
  ++
  get
  --
  put
  clear
  add "command*"
  push
  jump parse
block.end.25526:
testis "comment*comment*"
jumpfalse block.end.25640
  clear
  get
  add "\n"
  ++
  get
  --
  put
  clear
  add "comment*"
  push
  jump parse
block.end.25640:
# -----------------------
# 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.26383
  # 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.26383:
#-----------------------------------------
# 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.26655
  clear
  add "endtext*"
  push
  get
  --
  put
  ++
  clear
  jump parse
block.end.26655:
#-----------------------------------------
# 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.26966
  clear
  add "begintext*"
  push
  get
  --
  put
  ++
  clear
  jump parse
block.end.26966:
#--------------------------------------------
# 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.27664
  clear
  # check if command requires parameter
  get
  testis "add"
  jumptrue 20
  testis "until"
  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.27534
    put
    clear
    add "Pep: '"
    get
    add "'"
    add " << command needs an argument, on line "
    ll
    add " of script.\n"
    print
    clear
    quit
  block.end.27534:
  clear
  add "command*"
  # no need to format tape cells because current cell contains word
  push
  jump parse
block.end.27664:
#-----------------------------------------
# ebnf: commandset := command , command ;
testis "command*command*"
jumptrue 4
testis "commandset*command*"
jumptrue 2 
jump block.end.27988
  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.27988:
#-------------------
# 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.29011
  # set accumulator == 0
  zero
  testbegins "begin"
  jumpfalse block.end.28304
    clear
    add "testbegins "
  block.end.28304:
  testbegins "end"
  jumpfalse block.end.28343
    clear
    add "testends "
  block.end.28343:
  testbegins "quote"
  jumpfalse block.end.28382
    clear
    add "testis "
  block.end.28382:
  testbegins "class"
  jumpfalse block.end.28424
    clear
    add "testclass "
  block.end.28424:
  # clear the tapecell for testeof and testtape because
  # they take no arguments. 
  testbegins "eof"
  jumpfalse block.end.28556
    clear
    put
    add "testeof "
  block.end.28556:
  testbegins "tapetest"
  jumpfalse block.end.28605
    clear
    put
    add "testtape "
  block.end.28605:
  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.29011:
#-------------------
# 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.29980
  # set accumulator == 0
  zero
  testbegins "notbegin"
  jumpfalse block.end.29310
    clear
    add "testbegins "
  block.end.29310:
  testbegins "notend"
  jumpfalse block.end.29352
    clear
    add "testends "
  block.end.29352:
  testbegins "notquote"
  jumpfalse block.end.29394
    clear
    add "testis "
  block.end.29394:
  testbegins "notclass"
  jumpfalse block.end.29439
    clear
    add "testclass "
  block.end.29439:
  # clear the tapecell for testeof and testtape because
  # they take no arguments. 
  testbegins "noteof"
  jumpfalse block.end.29574
    clear
    put
    add "testeof "
  block.end.29574:
  testbegins "nottapetest"
  jumpfalse block.end.29626
    clear
    put
    add "testtape "
  block.end.29626:
  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.29980:
#-------------------
# 3 tokens
#-------------------
pop
#-----------------------------
# some 3 token errors!!!
# there are many other of these errors but I am not going
# to write them all.
testis "{*quote*;*"
jumptrue 8
testis "{*begintext*;*"
jumptrue 6
testis "{*endtext*;*"
jumptrue 4
testis "{*class*;*"
jumptrue 2 
jump block.end.30421
  push
  push
  push
  add "error near line "
  ll
  add " (char "
  cc
  add ")"
  add " of script (misplaced semicolon?) \n"
  print
  clear
  quit
block.end.30421:
# to simplify subsequent tests, transmogrify a single command
# to a commandset (multiple commands).
testis "{*command*}*"
jumpfalse block.end.30617
  clear
  add "{*commandset*}*"
  push
  push
  push
  jump parse
block.end.30617:
# rule 
#',' ortestset ::= ',' test '{'
# trigger a transmogrification from test to ortestset token
# and 
# '.' andtestset ::= '.' test '{'
testis ",*test*{*"
jumpfalse block.end.30854
  clear
  add ",*ortestset*{*"
  push
  push
  push
  jump parse
block.end.30854:
# trigger a transmogrification from "test" to "andtest" by
# looking backwards in the stack
testis ".*test*{*"
jumpfalse block.end.31091
  # the jump counter is 1 too high for AND tests
  a-
  clear
  add ".*andtestset*{*"
  push
  push
  push
  jump parse
block.end.31091:
# errors! mixing AND and OR concatenation
testis ",*andtestset*{*"
jumptrue 4
testis ".*ortestset*{*"
jumptrue 2 
jump block.end.31423
  # 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.31423:
#--------------------------------------------
# ebnf: command := keyword , quoted-text , ";" ;
# format: add "text";
testis "word*quote*;*"
jumpfalse block.end.33089
  clear
  get
  testis "replace"
  jumpfalse block.end.31763
    # error 
    add "< command requires 2 parameters, not 1 \n"
    add "near line "
    ll
    add " of script. \n"
    print
    clear
    quit
  block.end.31763:
  testis "add"
  jumptrue 18
  testis "until"
  jumptrue 16
  testis "while"
  jumptrue 14
  testis "whilenot"
  jumptrue 12
  testis "escape"
  jumptrue 10
  testis "mark"
  jumptrue 8
  testis "go"
  jumptrue 6
  testis "unescape"
  jumptrue 4
  testis "delim"
  jumptrue 2 
  jump block.end.32901
    # 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.32603
      add " "
      ++
      get
      replace "\n" "\\n\"\nadd \""
      --
      put
      ++
      clear
      jump parse
    block.end.32603:
    # maybe it would be useful for the until command to 
    # allow multiline as well
    testis "until"
    jumpfalse block.end.32826
      add " "
      ++
      get
      replace "\n" "\\n"
      --
      put
      ++
      clear
      jump parse
    block.end.32826:
    add " "
    ++
    get
    --
    put
    ++
    clear
    jump parse
  block.end.32901:
  # error, superfluous argument
  add ": command does not take an argument \n"
  add "near line "
  ll
  add " of script. \n"
  print
  clear
  #state
  quit
block.end.33089:
#----------------------------------
# format: "while [:alpha:] ;" or whilenot [a-z] ;
testis "word*class*;*"
jumpfalse block.end.33597
  clear
  get
  testis "while"
  jumptrue 4
  testis "whilenot"
  jumptrue 2 
  jump block.end.33447
    clear
    add "command*"
    push
    # a command plus argument, eg while [a-z] 
    --
    get
    add " "
    ++
    get
    --
    put
    ++
    clear
    jump parse
  block.end.33447:
  # error 
  add " < command cannot have a class argument \n"
  add "line "
  ll
  add ": error in script \n"
  print
  clear
  quit
block.end.33597:
# -------------------------------
# 4 tokens
# -------------------------------
pop
#-------------------------------------
# ebnf:     command := replace , quote , quote , ";" ;
# example:  replace "and" "AND" ; 
testis "word*quote*quote*;*"
jumpfalse block.end.34258
  clear
  get
  testis "replace"
  jumpfalse block.end.34138
    clear
    add "command*"
    push
    #---------------------------
    # a command plus 2 arguments, eg replace "this" "that"
    --
    get
    add " "
    ++
    get
    add " "
    ++
    get
    --
    --
    put
    ++
    clear
    jump parse
  block.end.34138:
  add " << command does not take 2 quoted arguments. \n"
  add " on line "
  ll
  add " of script.\n"
  quit
block.end.34258:
#-------------------------------------
# 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.34642
  clear
  ++
  ++
  get
  --
  --
  put
  clear
  add "beginblock*"
  push
  jump parse
block.end.34642:
# -------------
# 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.35566
  testbegins "begin"
  jumpfalse block.end.34971
    clear
    add "testbegins "
  block.end.34971:
  testbegins "end"
  jumpfalse block.end.35011
    clear
    add "testends "
  block.end.35011:
  testbegins "quote"
  jumpfalse block.end.35051
    clear
    add "testis "
  block.end.35051:
  testbegins "class"
  jumpfalse block.end.35094
    clear
    add "testclass "
  block.end.35094:
  # clear the tapecell for testeof and testtape because
  # they take no arguments. 
  testbegins "eof"
  jumpfalse block.end.35229
    clear
    put
    add "testeof "
  block.end.35229:
  testbegins "tapetest"
  jumpfalse block.end.35279
    clear
    put
    add "testtape "
  block.end.35279:
  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.35566:
# 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.36363
  testbegins "notbegin"
  jumpfalse block.end.35838
    clear
    add "testbegins "
  block.end.35838:
  testbegins "notend"
  jumpfalse block.end.35881
    clear
    add "testends "
  block.end.35881:
  testbegins "notquote"
  jumpfalse block.end.35924
    clear
    add "testis "
  block.end.35924:
  testbegins "notclass"
  jumpfalse block.end.35970
    clear
    add "testclass "
  block.end.35970:
  testbegins "noteof"
  jumpfalse block.end.36017
    clear
    put
    add "testeof "
  block.end.36017:
  testbegins "nottapetest"
  jumpfalse block.end.36070
    clear
    put
    add "testtape "
  block.end.36070:
  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.36363:
# 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.37293
  testbegins "begin"
  jumpfalse block.end.36907
    clear
    add "testbegins "
  block.end.36907:
  testbegins "end"
  jumpfalse block.end.36947
    clear
    add "testends "
  block.end.36947:
  testbegins "quote"
  jumpfalse block.end.36987
    clear
    add "testis "
  block.end.36987:
  testbegins "class"
  jumpfalse block.end.37030
    clear
    add "testclass "
  block.end.37030:
  testbegins "eof"
  jumpfalse block.end.37074
    clear
    put
    add "testeof "
  block.end.37074:
  testbegins "tapetest"
  jumpfalse block.end.37124
    clear
    put
    add "testtape "
  block.end.37124:
  get
  add "\n"
  add "jumpfalse "
  count
  add "\n"
  ++
  ++
  get
  --
  --
  put
  clear
  add "andtestset*{*"
  push
  push
  a+
  a+
  jump parse
block.end.37293:
# 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.38094
  testbegins "notbegin"
  jumpfalse block.end.37694
    clear
    add "testbegins "
  block.end.37694:
  testbegins "notend"
  jumpfalse block.end.37737
    clear
    add "testends "
  block.end.37737:
  testbegins "notquote"
  jumpfalse block.end.37780
    clear
    add "testis "
  block.end.37780:
  testbegins "notclass"
  jumpfalse block.end.37826
    clear
    add "testclass "
  block.end.37826:
  testbegins "noteof"
  jumpfalse block.end.37873
    clear
    put
    add "testeof "
  block.end.37873:
  testbegins "nottapetest"
  jumpfalse block.end.37926
    clear
    put
    add "testtape "
  block.end.37926:
  get
  add "\n"
  add "jumptrue "
  count
  add "\n"
  ++
  ++
  get
  --
  --
  put
  clear
  add "andtestset*{*"
  push
  push
  a+
  a+
  jump parse
block.end.38094:
#-------------------------------------
# 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.39165
  # indent the assembled code for readability
  testbegins "test*{*"
  jumpfalse block.end.38715
    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.38715:
  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.39165:
# -------------
# multi-token end-of-stream errors
# not a comprehensive list of errors...
testeof 
jumpfalse block.end.39941
  testends "begintext*"
  jumptrue 10
  testends "endtext*"
  jumptrue 8
  testends "test*"
  jumptrue 6
  testends "ortestset*"
  jumptrue 4
  testends "andtestset*"
  jumptrue 2 
  jump block.end.39472
    add "  Error near end of script at line "
    ll
    add ". Test with no brace block? \n"
    print
    clear
    quit
  block.end.39472:
  testends "quote*"
  jumptrue 6
  testends "class*"
  jumptrue 4
  testends "word*"
  jumptrue 2 
  jump block.end.39684
    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.39684:
  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.39937
    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.39937:
block.end.39941:
# put the 4 (or less) tokens back on the stack
push
push
push
push
testeof 
jumpfalse block.end.41982
  #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.40834
    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.40834:
  testis "beginblock*commandset*"
  jumptrue 4
  testis "beginblock*command*"
  jumptrue 2 
  jump block.end.41474
    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.41474:
  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.41982:
# not eof
# there is an implicit .restart command here (jump start)
jump start