ginsh/ginsh.l

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