core: parser: Add parser groundwork

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

1 files changed, 48 insertions, 0 deletions

diff --git a/core/parser.c b/core/parser.c
new file mode 100644
index 0000000..727d5e1
--- /dev/null
+++ b/core/parser.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2026, Apollo Telephone Laboratories.
+ * Provided under the BSD-3 clause.
+ */
+
+#include "defconf/parser.h"
+#include "defconf/lexer.h"
+#include "defconf/token.h"
+
+/* Symbolic token */
+#define SYMTOK(TOKSTR) \
+    "[" TOKSTR "]"
+
+/* Literal token */
+#define TOKLIT(TOKSTR)  \
+    "'" TOKSTR "'"
+
+/* Safe macro to convert token type to string */
+#define TOKSTR(TT)      \
+    ((TT) >= _TT_MAX)   \
+        ? "bad"         \
+        : toktab[(TT)]
+
+/* Token to string table */
+static const char *toktab[_TT_MAX] = {
+    [TT_NONE]       = SYMTOK("none"),
+    [TT_DEFINE]     = SYMTOK("define"),
+    [TT_TRUE]       = TOKLIT("true"),
+    [TT_FALSE]      = TOKLIT("false"),
+    [TT_INTLIT]     = SYMTOK("int"),
+    [TT_IDENT]      = SYMTOK("ident")
+};
+
+int
+parse_begin(struct defconf_state *state)
+{
+    struct token tok;
+
+    if (state == NULL) {
+        return -1;
+    }
+
+    while (lexer_scan(state, &tok) == 0) {
+        printf("got %s\n", TOKSTR(tok.type));
+    }
+
+    return 0;
+}