Premier exercice

lexical/example.l

@@ -0,0 +1,29 @@
+%option noyywrap
+
+%{
+int lines = 1;  // On compte la première ligne
+%}
+
+DIG	[0-9]
+HEX 0x[0-9A-Fa-f]+
+
+%%
+
+{HEX}	{ printf("hex(%d)", strtol(yytext, NULL, 16)); }
+{DIG}+	{ printf("int(%d)", atoi(yytext)); }
+"if"	{ printf("IF"); }
+"then"	{ printf("THEN"); }
+"else"	{ printf("ELSE"); }
+\n		{ lines++; }
+.		{ /* Pour tous les autres caractères, on ne fait rien */ }
+
+%%
+
+int main (int argc, char **argv)
+{
+	if (argc > 1) yyin = fopen(argv[1], "r");
+	yylex();
+	puts("");
+	printf("%d lignes\n", lines);
+	return 0;
+}

lexical/flux.l

@@ -0,0 +1,34 @@
+%option noyywrap
+
+%{
+enum { T_INT = 1, T_CHAR = 2 };
+union {
+	int i;
+	char c;
+} data; 
+%}
+
+DIG	[0-9]
+
+%%
+
+{DIG}+	{ data.i = atoi(yytext); return T_INT; }
+[+*()]	{ data.c = *yytext; return T_CHAR; }
+[ \n]   { /* ignore */ }
+
+%%
+
+int main (int argc, char **argv)
+{
+	int token;
+	if (argc > 1) yyin = fopen(argv[1],"r");
+	while (token = yylex())
+	{
+		switch(token)
+		{
+		  	case T_INT: printf("int(%d)  ",data.i); break;
+		  	case T_CHAR: printf("'%c'  ",data.c); break;
+		}
+	}
+	puts("");
+}

lexical/string.l

@@ -0,0 +1,26 @@
+%option noyywrap
+
+DIG	[0-9]
+
+%%
+
+{DIG}+	{ printf("int(%d)  ",atoi(yytext)); }
+[+*()]	{ printf("'%c'  ",*yytext); }
+[ \n]   { /* ignore */ }
+
+%%
+
+int main (int argc, char **argv)
+{
+	YY_BUFFER_STATE buffer;
+
+	buffer = yy_scan_string("100+5*2");
+	yylex();
+	yy_delete_buffer(buffer);
+
+	buffer = yy_scan_string("20+30");
+	yylex();
+	yy_delete_buffer(buffer);
+
+	puts("");
+}