ginsh/ginsh_lexer.ll

   1 /*
   2  *  ginsh.l - GiNaC Interactive Shell, lexical analyzer definition
   3  *
   4  *  This file must be processed with flex
   5  */
   6
   7
   8 /*
   9  *  Definitions
  10  */
  11
  12 %{
  13 #include "config.h"
  14
  15 #include <stdio.h>
  16 extern "C" {
  17 #include <readline/readline.h>
  18 #include <readline/history.h>
  19 }
  20 #include <map>
  21
  22 #include <ginac/ginac.h>
  23 #include "ginsh.h"
  24
  25 #include "ginsh_parser.h"
  26
  27 #define YY_INPUT(buf, result, max_size) (result = ginsh_input(buf, max_size))
  28
  29 // Table of all used symbols
  30 sym_tab syms;
  31
  32 // lex input function
  33 static int ginsh_input(char *buf, int max_size);
  34 %}
  35
  36         /* Abbreviations */
  37 D       [0-9]
  38 E       [elEL][-+]?{D}+
  39 A       [a-zA-Z_]
  40 AN      [0-9a-zA-Z_]
  41
  42
  43 /*
  44  *  Lexical rules
  45  */
  46
  47 %%
  48 [ \t\n]+                /* skip whitespace */
  49 \\$                     /* skip line continuations */
  50 "#".*                   /* skip comments starting with "#" */
  51 ^"!".*                  system(yytext + 1);     /* execute shell command */
  52
  53                         /* special values */
  54 Pi                      yylval = Pi; return T_LITERAL;
  55 EulerGamma              yylval = EulerGamma; return T_LITERAL;
  56 Catalan                 yylval = Catalan; return T_LITERAL;
  57 FAIL                    yylval = *new fail(); return T_LITERAL;
  58 I                       yylval = I; return T_NUMBER;
  59 Digits                  yylval = (long)Digits; return T_DIGITS;
  60
  61                         /* keywords */
  62 quit|exit               return T_QUIT;
  63 print                   return T_PRINT;
  64 time                    return T_TIME;
  65 xyzzy                   return T_XYZZY;
  66 inventory               return T_INVENTORY;
  67 look                    return T_LOOK;
  68 score                   return T_SCORE;
  69
  70                         /* comparison */
  71 "=="                    return T_EQUAL;
  72 "!="                    return T_NOTEQ;
  73 "<="                    return T_LESSEQ;
  74 ">="                    return T_GREATEREQ;
  75
  76                         /* last 1..3 expressions */
  77 \"                      return T_QUOTE;
  78 \"\"                    return T_QUOTE2;
  79 \"\"\"                  return T_QUOTE3;
  80
  81                         /* matrix delimiters */
  82 \[\[                    return T_MATRIX_BEGIN;
  83 \]\]                    return T_MATRIX_END;
  84
  85                         /* numbers */
  86 {D}+                    |
  87 {D}+"."{D}*({E})?       |
  88 {D}*"."{D}+({E})?       |
  89 {D}+{E}                 yylval = numeric(yytext); return T_NUMBER;
  90
  91                         /* symbols */
  92 {A}{AN}*                {
  93                                 if (syms.find(yytext) == syms.end())
  94                                         syms[yytext] = *(new symbol(yytext));
  95                                 yylval = syms[yytext];
  96                                 return T_SYMBOL;
  97                         }
  98
  99                         /* everything else */
 100 .                       return *yytext;
 101
 102 %%
 103
 104
 105 /*
 106  *  Routines
 107  */
 108
 109 static int line_length = 0;
 110 static char *line_read = NULL;
 111 static char *line_ptr;
 112
 113 // Input function that uses libreadline for interactive input
 114 static int ginsh_input(char *buf, int max_size)
 115 {
 116         int result;
 117         if (yy_current_buffer->yy_is_interactive) {
 118                 int actual;
 119
 120                 // Do we need to read a new line?
 121                 if (line_length == 0) {
 122
 123                         // Free old line
 124                         if (line_read)
 125                                 free(line_read);
 126
 127                         // Read new line, prompt "> "
 128                         line_read = line_ptr = readline("> ");
 129
 130                         // EOF?
 131                         if (!line_read) {
 132                                 line_length = 0;
 133                                 return YY_NULL;
 134                         }
 135
 136                         // Add non-empty lines to history
 137                         line_length = strlen(line_read) + 1;
 138                         if (line_length > 1)
 139                                 add_history(line_read);
 140
 141                         // Reappend trailing '\n' which is stripped by readline()
 142                         line_read[line_length - 1] = '\n';
 143                 }
 144
 145                 // Copy data to lex buffer
 146                 actual = line_length > max_size ? max_size : line_length;
 147                 memcpy(buf, line_ptr, actual);
 148                 line_length -= actual;
 149                 line_ptr += actual;
 150                 result = actual;
 151
 152         } else if (((result = fread(buf, 1, max_size, yyin)) == 0) && ferror(yyin))
 153                 YY_FATAL_ERROR("input in flex scanner failed");
 154
 155         return result;
 156 }
 157
 158 // Scanner terminates on EOF
 159 int yywrap()
 160 {
 161         return 1;
 162 }