commit 2058cc1dd9fa0ec57fe9191f66ed8b2790b31a25
parent f65ebced503d321852395e8ac8ad71d68cbb60c9
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 22 Dec 1993 19:14:58 -0200
analizador lexico de LUA
Diffstat:
| A | lex.c | | | 207 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 207 insertions(+), 0 deletions(-)
diff --git a/lex.c b/lex.c
@@ -0,0 +1,207 @@
+char *rcs_lex = "$Id$";
+/*$Log$*/
+
+#include <ctype.h>
+#include <math.h>
+
+#include "opcode.h"
+#include "hash.h"
+#include "inout.h"
+#include "table.h"
+#include "y.tab.h"
+
+#define next() { current = input(); }
+#define save(x) { *yytextLast++ = (x); }
+#define save_and_next() { save(current); next(); }
+
+static int current;
+static char yytext[256];
+static char *yytextLast;
+
+static Input input;
+
+void lua_setinput (Input fn)
+{
+ current = ' ';
+ input = fn;
+}
+
+char *lua_lasttext (void)
+{
+ *yytextLast = 0;
+ return yytext;
+}
+
+
+static struct
+ {
+ char *name;
+ int token;
+ } reserved [] = {
+ {"and", AND},
+ {"do", DO},
+ {"else", ELSE},
+ {"elseif", ELSEIF},
+ {"end", END},
+ {"function", FUNCTION},
+ {"if", IF},
+ {"local", LOCAL},
+ {"nil", NIL},
+ {"not", NOT},
+ {"or", OR},
+ {"repeat", REPEAT},
+ {"return", RETURN},
+ {"then", THEN},
+ {"until", UNTIL},
+ {"while", WHILE} };
+
+#define RESERVEDSIZE (sizeof(reserved)/sizeof(reserved[0]))
+
+
+int findReserved (char *name)
+{
+ int l = 0;
+ int h = RESERVEDSIZE - 1;
+ while (l <= h)
+ {
+ int m = (l+h)/2;
+ int comp = strcmp(name, reserved[m].name);
+ if (comp < 0)
+ h = m-1;
+ else if (comp == 0)
+ return reserved[m].token;
+ else
+ l = m+1;
+ }
+ return 0;
+}
+
+
+int yylex ()
+{
+ while (1)
+ {
+ yytextLast = yytext;
+ switch (current)
+ {
+ case 0: return 0;
+ case '\n': lua_linenumber++;
+ case ' ':
+ case '\t':
+ save_and_next();
+ continue;
+
+ case '-':
+ save_and_next();
+ if (current != '-') return '-';
+ do { save_and_next(); } while (current != '\n' && current != 0);
+ continue;
+
+ case '<':
+ save_and_next();
+ if (current != '=') return '<';
+ else { save_and_next(); return LE; }
+
+ case '>':
+ save_and_next();
+ if (current != '=') return '>';
+ else { save_and_next(); return GE; }
+
+ case '~':
+ save_and_next();
+ if (current != '=') return '~';
+ else { save_and_next(); return NE; }
+
+ case '"':
+ case '\'':
+ {
+ int del = current;
+ next(); /* skip the delimiter */
+ while (current != del)
+ {
+ switch (current)
+ {
+ case 0:
+ case '\n':
+ return WRONGTOKEN;
+ case '\\':
+ next(); /* do not save the '\' */
+ switch (current)
+ {
+ case 'n': save('\n'); next(); break;
+ case 't': save('\t'); next(); break;
+ case 'r': save('\r'); next(); break;
+ default : save('\\'); break;
+ }
+ break;
+ default:
+ save_and_next();
+ }
+ }
+ next(); /* skip the delimiter */
+ *yytextLast = 0;
+ yylval.vWord = lua_findconstant (yytext);
+ return STRING;
+ }
+
+ case 'a': case 'b': case 'c': case 'd': case 'e':
+ case 'f': case 'g': case 'h': case 'i': case 'j':
+ case 'k': case 'l': case 'm': case 'n': case 'o':
+ case 'p': case 'q': case 'r': case 's': case 't':
+ case 'u': case 'v': case 'w': case 'x': case 'y':
+ case 'z':
+ case 'A': case 'B': case 'C': case 'D': case 'E':
+ case 'F': case 'G': case 'H': case 'I': case 'J':
+ case 'K': case 'L': case 'M': case 'N': case 'O':
+ case 'P': case 'Q': case 'R': case 'S': case 'T':
+ case 'U': case 'V': case 'W': case 'X': case 'Y':
+ case 'Z':
+ case '_':
+ {
+ int res;
+ do { save_and_next(); } while (isalnum(current) || current == '_');
+ *yytextLast = 0;
+ res = findReserved(yytext);
+ if (res) return res;
+ yylval.vWord = lua_findsymbol(yytext);
+ return NAME;
+ }
+
+ case '.':
+ save_and_next();
+ if (current == '.')
+ {
+ save_and_next();
+ return CONC;
+ }
+ else if (!isdigit(current)) return '.';
+ /* current is a digit: goes through to number */
+ goto fraction;
+
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+
+ do { save_and_next(); } while (isdigit(current));
+ if (current == '.') save_and_next();
+fraction: while (isdigit(current)) save_and_next();
+ if (current == 'e' || current == 'E')
+ {
+ save_and_next();
+ if (current == '+' || current == '-') save_and_next();
+ if (!isdigit(current)) return WRONGTOKEN;
+ do { save_and_next(); } while (isdigit(current));
+ }
+ *yytextLast = 0;
+ yylval.vFloat = atof(yytext);
+ return NUMBER;
+
+ default:
+ {
+ int temp = current;
+ save_and_next();
+ return temp;
+ }
+ }
+ }
+}
+
