// code generated by "translate.go.pss" a pep script // http://bumble.sf.net/books/pars/tr/ // s.HasPrefix can be used instead of strings.HasPrefix package main import ( "fmt" "bufio" "strings" "strconv" "unicode" "io" "os" "unicode/utf8" ) // an alias for Println for brevity var pr = fmt.Println /* a machine for parsing */ type machine struct { SIZE int eof bool charsRead int linesRead int escape rune delimiter rune counter int work string stack []string cell int tape []string marks []string peep rune reader *bufio.Reader } // there is no special init for structures func newMachine(size int) *machine { mm := machine{SIZE: size} // mm.SIZE = 200 // how many elements in stack/tape/marks mm.eof = false // end of stream reached? mm.charsRead = 0 // how many chars already read mm.linesRead = 1 // how many lines already read mm.escape = '\\' mm.delimiter = '*' // push/pop delimiter (default "*") mm.counter = 0 // a counter for anything mm.work = "" // the workspace mm.stack = make([]string, 0, mm.SIZE) // stack for parse tokens mm.cell = 0 // current tape cell // slices not arrays mm.tape = make([]string, mm.SIZE, mm.SIZE) // a list of attribute for tokens mm.marks = make([]string, mm.SIZE, mm.SIZE) // marked tape cells // or dont initialse peep until "parse()" calls "setInput()" // check! this is not so simple mm.reader = bufio.NewReader(os.Stdin) var err error mm.peep, _, err = mm.reader.ReadRune() if err == io.EOF { mm.eof = true } else if err != nil { fmt.Fprintln(os.Stderr, "error:", err) os.Exit(1) } return &mm } // method syntax. // func (v * vertex) abs() float64 { ... } // multiline strings are ok ? func (mm *machine) printSizeError() { /* fmt.Println("Tape max size exceeded! " + "tape maximum size = (mm.size) " + "tape cell (current) = (mm.cell) " + " You can increase the array value in the go script " + " but normally this error indicates an error in your parsing " + " script. The only exception would be massively nested structures " + " in the source data."); */ } func (mm *machine) setInput(newInput string) { print("to be implemented") } // read one utf8 character from the input stream and // update the machine. func (mm *machine) read() { var err error if mm.eof { os.Exit(0) } mm.charsRead += 1 // increment lines if mm.peep == '\n' { mm.linesRead += 1 } mm.work += string(mm.peep) // check! mm.peep, _, err = mm.reader.ReadRune() if err == io.EOF { mm.eof = true } else if err != nil { fmt.Fprintln(os.Stderr, "error:", err) os.Exit(1) } } // remove escape character: trivial method ? // check the python code for this, and the c code in machine.interp.c func (mm *machine) unescapeChar(c string) { // if mm.work = "" { return } mm.work = strings.Replace(mm.work, "\\"+c, c, -1) } // add escape character : trivial func (mm *machine) escapeChar(c string) { mm.work = strings.Replace(mm.work, c, "\\"+c, -1) } /** a helper function to count trailing escapes */ func (mm *machine) countEscapes(suffix string) int { count := 0 ss := "" if strings.HasSuffix(mm.work, suffix) { ss = strings.TrimSuffix(mm.work, suffix) } for (strings.HasSuffix(ss, string(mm.escape))) { ss = strings.TrimSuffix(ss, string(mm.escape)) count++ } return count } // reads the input stream until the workspace ends with the // given character or text, ignoring escaped characters func (mm *machine) until(suffix string) { if mm.eof { return; } // read at least one character mm.read() for true { if mm.eof { return; } // we need to count the mm.Escape chars preceding suffix // if odd, keep reading, if even, stop if strings.HasSuffix(mm.work, suffix) { if (mm.countEscapes(suffix) % 2 == 0) { return } } mm.read() } } /* pop the last token from the stack into the workspace */ func (mm *machine) pop() bool { if len(mm.stack) == 0 { return false } // no, get last element of stack // a[len(a)-1] mm.work = mm.stack[len(mm.stack)-1] + mm.work // a = a[:len(a)-1] mm.stack = mm.stack[:len(mm.stack)-1] if mm.cell > 0 { mm.cell -= 1 } return true } // push the first token from the workspace to the stack func (mm *machine) push() bool { // dont increment the tape pointer on an empty push if mm.work == "" { return false } // push first token, or else whole string if no delimiter aa := strings.SplitN(mm.work, string(mm.delimiter), 2) if len(aa) == 1 { mm.stack = append(mm.stack, mm.work) mm.work = "" } else { mm.stack = append(mm.stack, aa[0]+string(mm.delimiter)) mm.work = aa[1] } mm.cell++ if mm.cell > mm.SIZE { // fix! mm.printState() } return true } // func (mm *machine) printState() { fmt.Printf("Stack %v Work[%s] Peep[%c] \n", mm.stack, mm.work, mm.peep) fmt.Printf("Acc:%v Esc:%c Delim:%c Chars:%v", mm.counter, mm.escape, mm.delimiter, mm.charsRead) fmt.Printf(" Lines:%v Cell:%v EOF:%v \n", mm.linesRead, mm.cell, mm.eof) for ii, vv := range mm.tape { fmt.Printf("%v [%s] \n", ii, vv) if ii > 4 { return; } } } // this is where the actual parsing/compiling code should go // so that it can be used by other go classes/objects. Also // should have a stream argument. func (mm *machine) parse(s string) { } /* adapt for clop and clip */ func trimLastChar(s string) string { r, size := utf8.DecodeLastRuneInString(s) if r == utf8.RuneError && (size == 0 || size == 1) { size = 0 } return s[:len(s)-size] } func (mm *machine) clip() { cc, _ := utf8.DecodeLastRuneInString(mm.work) mm.work = strings.TrimSuffix(mm.work, string(cc)) } func (mm *machine) clop() { _, size := utf8.DecodeRuneInString(mm.work) mm.work = mm.work[size:] } type fn func(rune) bool // eg unicode.IsLetter('x') /* check whether the string s only contains runes of type determined by the typeFn function */ func isInClass(typeFn fn, s string) bool { if s == "" { return false; } for _, rr := range s { //if !unicode.IsLetter(rr) { if !typeFn(rr) { return false } } return true } /* range in format 'a,z' */ func isInRange(start rune, end rune, s string) bool { if s == "" { return false; } for _, rr := range s { if (rr < start) || (rr > end) { return false } } return true } /* list of runes (unicode chars ) */ func isInList(list string, s string) bool { return strings.ContainsAny(s, list) } func main() { var size = 200 var mm = newMachine(size); var restart = false; // the go compiler complains when modules are imported but // not used, also if vars are not used. if restart {}; unicode.IsDigit('0'); strconv.Itoa(0); for !mm.eof { /* lex block */ for true { mm.read() /* read */ // make character number relative to line if (mm.work == "\n") { mm.charsRead = 0 /* nochars */ mm.work = "" // clear restart = true; break // restart } if (isInClass(unicode.IsSpace, mm.work)) { mm.work = "" // clear restart = true; break // restart } if (isInRange('0','9', mm.work)) { /* while */ for isInRange('0','9', string(mm.peep)) { if mm.eof { break } mm.read() } mm.tape[mm.cell] = mm.work /* put */ mm.work = "" // clear mm.work += "number*" mm.push(); break } // literal tokens if (mm.work == "," || mm.work == "-" || mm.work == "+" || mm.work == "[" || mm.work == "]") { mm.tape[mm.cell] = mm.work /* put */ mm.work += "*" mm.push(); break } break } if restart { restart = false; continue; } // parse block for true { // The parse/compile phase // -------------- // 1 token mm.pop(); // -------------- // 2 tokens mm.pop(); // some errors if (mm.work == "[*,*" || mm.work == ",*,*" || mm.work == ",*]*" || mm.work == "number*number*" || mm.work == "number*[*") { mm.work = "" // clear mm.work += "[format error] at line/char " mm.work += strconv.Itoa(mm.linesRead) /* lines */ mm.work += "/" mm.work += strconv.Itoa(mm.charsRead) /* chars */ mm.work += "\n" fmt.Printf("%s", mm.work) // print os.Exit(0) } // empty arrays if (mm.work == "[*]*") { mm.work = "" // clear mm.work += "array*" mm.push(); continue } // signed numbers, but the value is ignored if (mm.work == "-*number*" || mm.work == "+*number*") { mm.clop() mm.clop() mm.push(); continue } // next item in array if (mm.work == "[*number*" || mm.work == "[*array*") { mm.work = "" // clear mm.work += "[*items*" mm.push(); mm.push(); continue } // -------------- // 3 tokens mm.pop(); // arrays if (mm.work == "[*items*]*") { mm.work = "" // clear mm.work += "array*" mm.push(); continue } if (mm.work == "items*,*number*" || mm.work == "items*,*array*") { mm.work = "" // clear mm.work += "items*" mm.push(); continue } mm.push(); mm.push(); mm.push(); if (mm.eof) { for mm.pop() {} /* unstack */ if (mm.work == "array*") { mm.work = "" // clear mm.work += "A numeric array!\n" fmt.Printf("%s", mm.work) // print os.Exit(0) } for mm.push() {} /* stack */ mm.work += "Not a numeric array\n" fmt.Printf("%s", mm.work) // print mm.work = "" // clear mm.work += "The input parsed as:" fmt.Printf("%s", mm.work) // print mm.work = "" // clear for mm.pop() {} /* unstack */ mm.work += "\n" fmt.Printf("%s", mm.work) // print } break } // parse } } // end of generated 'go' code