core: lexer: Add keyword tokens

Signed-off-by: Chloe M. <chloe@mirocom.org>

core/lexer.c

@@ -7,6 +7,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <ctype.h>
+#include <string.h>
 #include "cescal/lexer.h"
 #include "cescal/log.h"
 #include "cescal/ptrbox.h"
@@ -135,6 +136,49 @@ lexer_scan_ident(struct cescal_state *state, char lc, struct token *res)
     return 0;
 }
 
+/*
+ * Checks if an identifier token is actually a keyword
+ *
+ * @state:   Compiler state
+ * @res:     Token result
+ */
+static void
+lexer_check_kw(struct cescal_state *state, struct token *res)
+{
+    if (state == NULL || res == NULL) {
+        return;
+    }
+
+    switch (*res->s) {
+    case 'p':
+        if (strcmp(res->s, "pub") == 0) {
+            res->type = TT_PUB;
+            return;
+        }
+
+        if (strcmp(res->s, "proc") == 0) {
+            res->type = TT_PROC;
+            return;
+        }
+
+        break;
+    case 'b':
+        if (strcmp(res->s, "begin") == 0) {
+            res->type = TT_BEGIN;
+            return;
+        }
+
+        break;
+    case 'e':
+        if (strcmp(res->s, "end") == 0) {
+            res->type = TT_END;
+            return;
+        }
+
+        break;
+    }
+}
+
 int
 lexer_nom(struct cescal_state *state, struct token *res)
 {
@@ -164,6 +208,7 @@ lexer_nom(struct cescal_state *state, struct token *res)
         return 0;
     default:
         if (lexer_scan_ident(state, c, res) == 0) {
+            lexer_check_kw(state, res);
             return 0;
         }
     }