core: Add lexer + parser groundwork

Signed-off-by: Ian Moffett <ian@mirocom.org>

include/cescal/lexer.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause
+ */
+
+#ifndef CESCAL_LEXER_H
+#define CESCAL_LEXER_H 1
+
+#include <stdint.h>
+#include <stddef.h>
+#include "cescal/token.h"
+#include "cescal/state.h"
+
+/*
+ * Consume a single token from the input source file
+ *
+ * @state: Compiler state
+ * @res:   Token result is written here
+ *
+ * Returns zero on success
+ */
+int lexer_nom(struct cescal_state *state, struct token *res);
+
+#endif  /* !CESCAL_LEXER_H */

include/cescal/parser.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause
+ */
+
+#ifndef CESCAL_PARSER_H
+#define CESCAL_PARSER_H 1
+
+#include "cescal/state.h"
+
+/*
+ * Begin parsing the input source file
+ *
+ * @state:  Compiler state
+ *
+ * Returns zero on success
+ */
+int parser_parse(struct cescal_state *state);
+
+#endif  /* !CESCAL_PARSER_H */

include/cescal/token.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause
+ */
+
+#ifndef CESCAL_TOKEN_H
+#define CESCAL_TOKEN_H 1
+
+/*
+ * Represents valid source file token types
+ */
+typedef enum {
+    TT_NONE,        /* [none] */
+    TT_IDENT,       /* [identifier] */
+    TT_INTLIT,      /* [0-9]+ */
+    TT_LPAREN,      /* '(' */
+    TT_RPAREN,      /* '( */
+    TT_COMMA,       /* ',' */
+    TT_RETURN,      /* 'return' */
+    TT_PUB,         /* 'pub' */
+    TT_PROC,        /* 'proc' */
+    TT_BEGIN,       /* 'begin' */
+    TT_END,         /* 'end' */
+} tt_t;
+
+/*
+ * Represents a source file token
+ *
+ * @type: Token type
+ */
+struct token {
+    tt_t type;
+    union {
+        char c;
+    };
+};
+
+#endif  /* !CESCAL_TOKEN_H */