core: lexer+parser: Handle integer literals

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

4 files changed, 64 insertions, 0 deletions

diff --git a/conf/defconf-00.conf b/conf/defconf-00.conf
index f2b152f..028c8c5 100644
--- a/conf/defconf-00.conf
+++ b/conf/defconf-00.conf
@@ -1,2 +1,3 @@
 define MEOW_YES     true
 define MEOW_NO      false
+define MEOW_COUNT   3
diff --git a/core/lexer.c b/core/lexer.c
index ac5194f..59aaa13 100644
--- a/core/lexer.c
+++ b/core/lexer.c
@@ -13,6 +13,7 @@
 
 /* Constants */
 #define MAX_KW_LEN 32
+#define MAX_NUM_LEN 20
 
 /*
  * Returns true if the given character is a whitespace character
@@ -126,6 +127,51 @@ lexer_scan_ident(struct defconf_state *state, int lc)
 }
 
 /*
+ * Scan a number
+ *
+ * @state:   Defconf state
+ * @lc:      Last character provided
+ * @result:  Result is written here
+ */
+static int
+lexer_scan_num(struct defconf_state *state, int lc, struct token *result)
+{
+    char c, buf[MAX_NUM_LEN + 1];
+    size_t bufind = 0;
+
+    if (state == NULL || result == NULL) {
+        return -1;
+    }
+
+    if (!isdigit(lc)) {
+        return -1;
+    }
+
+    buf[bufind++] = lc;
+    for (;;) {
+        if (bufind >= sizeof(buf) - 1) {
+            trace_fatal(state, "digits exceed maximum length\n");
+            return -1;
+        }
+
+        c = lexer_nom(state, false);
+        if (!isdigit(c)) {
+            lexer_putback(state, c);
+            buf[bufind] = '\0';
+
+            /* Set the token */
+            result->type = TT_INTLIT;
+            result->v = atoi(buf);
+            return 0;
+        }
+
+        buf[bufind++] = c;
+    }
+
+    return -1;
+}
+
+/*
  * Check if a keyword matches against known keywords
  *
  * @kw:         Keyword to check
@@ -172,6 +218,7 @@ lexer_scan(struct defconf_state *state, struct token *result)
 {
     int c;
     char *ident;
+    int error;
 
     if (state == NULL || result == NULL) {
         return -1;
@@ -192,6 +239,16 @@ lexer_scan(struct defconf_state *state, struct token *result)
         return 0;
     }
 
+    /* Is this a digit? */
+    if (isdigit(c)) {
+        error = lexer_scan_num(state, c, result);
+        if (error < 0) {
+            return -1;
+        }
+
+        return 0;
+    }
+
     trace_fatal(state, "unexpected token '%c'\n", c);
     return -1;
 }
diff --git a/core/parser.c b/core/parser.c
index 698691e..79fda93 100644
--- a/core/parser.c
+++ b/core/parser.c
@@ -50,6 +50,10 @@ token_to_data(struct token *tok, struct data_value *result)
         result->v = 0;
         result->type = DATA_TYPE_INT;
         return 0;
+    case TT_INTLIT:
+        result->v = tok->v;
+        result->type = DATA_TYPE_INT;
+        return 0;
     default:
         return -1;
     }
diff --git a/head/defconf/token.h b/head/defconf/token.h
index 4a69311..9db1a7e 100644
--- a/head/defconf/token.h
+++ b/head/defconf/token.h
@@ -25,12 +25,14 @@ typedef enum {
  * @type:  Token type
  * @c:     Associated character
  * @s:     Associated string
+ * @v:     Associated integer
  */
 struct token {
     tt_t type;
     union {
         char c;
         char *s;
+        size_t v;
     };
 };