1 files changed, 100 insertions, 0 deletions
diff --git a/lib/parse.c b/lib/parse.c
new file mode 100644
index 0000000..0bf2396
--- /dev/null
+++ b/lib/parse.c
@@ -0,0 +1,100 @@
+/* Aplwc - A Programming Language With Constraints
+ *
+ * Copyright (C) 2026 Peter Mikkelsen <petermikkelsen10@gmail.com>
+ *
+ * This file is part of aplwc.
+ *
+ * Aplwc is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Aplwc is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with aplwc.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <aplwc.h>
+#include "aplwc_internal.h"
+
+static enum aplwc_token_tag peek(struct aplwc_eval_context *);
+static struct aplwc_token *match(struct aplwc_eval_context *, enum aplwc_token_tag);
+static void emit(struct aplwc_eval_context *, enum aplwc_ast_tag, struct aplwc_ast **);
+static char *token_text(struct aplwc_eval_context *, struct aplwc_token *);
+static void parse_syscmd(struct aplwc_eval_context *, struct aplwc_ast **);
+
+void
+aplwc_parse(struct aplwc_eval_context *context)
+{
+	context->token_offset = 0;
+
+	if(peek(context) == APLWC_TOKEN_SYSCMD)
+		parse_syscmd(context, &context->ast);
+
+	if(context->ast == NULL)
+		emit(context, APLWC_AST_ERROR, &context->ast);
+}
+
+static enum aplwc_token_tag
+peek(struct aplwc_eval_context *context)
+{
+	enum aplwc_token_tag tag = -1;
+	
+	if(context->token_offset < context->n_tokens)
+		tag = context->tokens[context->token_offset]->tag;
+	return tag;
+}
+
+static struct aplwc_token *
+match(struct aplwc_eval_context *context, enum aplwc_token_tag tag)
+{
+	struct aplwc_token *tok = NULL;
+	
+	if(peek(context) == tag)
+		tok = context->tokens[context->token_offset++];
+	return tok;
+}
+
+static void
+emit(struct aplwc_eval_context *context, enum aplwc_ast_tag tag, struct aplwc_ast **ast)
+{
+	if((*ast) != NULL)
+		aplwc_free_ast(context->aplwc, *ast);
+	
+	*ast = context->aplwc->alloc(sizeof(**ast));
+	memset(*ast, 0, sizeof(**ast));
+	(*ast)->tag = tag;
+}
+
+static char *
+token_text(struct aplwc_eval_context *context, struct aplwc_token *tok)
+{
+	size_t len = tok->offset_end - tok->offset_start + 1;
+	char *text = context->aplwc->alloc(len + 1);
+	memcpy(text, context->text + tok->offset_start, len);
+	text[len] = 0;
+	return text;
+}
+
+static void
+parse_syscmd(struct aplwc_eval_context *context, struct aplwc_ast **ast)
+{
+	struct aplwc_token *tok = match(context, APLWC_TOKEN_SYSCMD);
+
+	char *name = token_text(context, tok);
+	struct aplwc_syscmd *syscmd = aplwc_lookup_syscmd(context->aplwc, name+1);
+	context->aplwc->free(name);
+	
+	if(syscmd){
+		emit(context, APLWC_AST_SYSCMD, ast);
+		(*ast)->data.syscmd.syscmd = syscmd;
+		(*ast)->data.syscmd.args = aplwc_strdup(context->aplwc, "");
+	}else
+		emit(context, APLWC_AST_ERROR, ast);
+}