1 files changed, 37 insertions, 0 deletions
diff --git a/simple-c/lexer.l b/simple-c/lexer.l
new file mode 100644
index 0000000..be983d1
--- /dev/null
+++ b/simple-c/lexer.l
@@ -0,0 +1,37 @@
+%{
+#include "parser.h"
+#define YY_USER_ACTION yylloc.first_line = yylloc.last_line = yylineno;
+%}
+
+%option noyywrap
+
+DIGIT [0-9]
+
+%%
+
+"-" { return MINUS; }
+"+" { return PLUS; }
+"*" { return MULT; }
+"/" { return DIV; }
+"=" { return EQUAL; }
+"(" { return L_PAREN; }
+")" { return R_PAREN; }
+
+(\.{DIGIT}+)|({DIGIT}+(\.{DIGIT}*)?([eE][+-]?[0-9]+)?) {
+    yylval.dval = atof(yytext);
+    return NUMBER;
+}
+
+[ \t]+ { /* ignore spaces */ }
+
+"\n" { return END; }
+
+. {
+    printf(
+        "Error at line %d: unrecognized symbol \"%s\"\n",
+        yylloc.first_line,
+        yytext);
+    exit(0);
+}
+
+%%