From dca0aba18375810bc13695169eb27e41494ccc58 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Mon, 25 Nov 2024 16:49:07 +0000
Subject: [PATCH] lang: ast: implement parsing 'use' statements

---
 lang/ast/unit-import.c      | 103 ++++++++++++++++++++++++++++++++++++
 lang/ast/unit.c             |   8 +++
 lang/include/ivy/lang/ast.h |   2 +-
 3 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 lang/ast/unit-import.c

diff --git a/lang/ast/unit-import.c b/lang/ast/unit-import.c
new file mode 100644
index 0000000..3ffd0a1
--- /dev/null
+++ b/lang/ast/unit-import.c
@@ -0,0 +1,103 @@
+#include <blue/object/string.h>
+#include <ivy/lang/lex.h>
+#include <stdio.h>
+
+#include "ctx.h"
+#include "node.h"
+
+struct unit_import_parser_state {
+	struct parser_state s_base;
+	int s_prev_token;
+};
+
+static enum ivy_status parse_dot(struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct unit_import_parser_state *state
+		= parser_get_state(ctx, struct unit_import_parser_state);
+
+	if (state->s_prev_token != IVY_TOK_IDENT) {
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	state->s_prev_token = IVY_SYM_DOT;
+	return IVY_OK;
+}
+
+static enum ivy_status parse_ident(struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct unit_import_parser_state *state
+		= parser_get_state(ctx, struct unit_import_parser_state);
+
+	struct ivy_ast_unit_import_node *node = (struct ivy_ast_unit_import_node *)(state->s_base.s_node);
+
+	if (state->s_prev_token == IVY_TOK_IDENT) {
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	b_queue_push_back(&node->n_ident, &tok->t_entry);
+
+	state->s_prev_token = IVY_TOK_IDENT;
+	return IVY_OK;
+}
+
+static enum ivy_status parse_linefeed(struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	struct unit_import_parser_state *state
+		= parser_get_state(ctx, struct unit_import_parser_state);
+
+	if (state->s_prev_token != IVY_TOK_IDENT) {
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
+	return IVY_OK;
+}
+
+static enum ivy_status add_child(
+	struct ivy_ast_node *parent, struct ivy_ast_node *child)
+{
+	return IVY_ERR_NOT_SUPPORTED;
+}
+
+static void print(struct ivy_ast_node *node)
+{
+	struct ivy_ast_unit_import_node *unit_import = (struct ivy_ast_unit_import_node *)node;
+	b_string *str = b_string_create();
+
+	b_queue_iterator it = {0};
+	b_queue_foreach (&it, &unit_import->n_ident) {
+		struct ivy_token *tok = b_unbox(struct ivy_token, it.entry, t_entry);
+
+		if (b_string_get_size(str, B_STRLEN_NORMAL) > 0) {
+			b_string_append_cstr(str, ".");
+		}
+
+		b_string_append_cstr(str, tok->t_str);
+	}
+
+	printf("%s(%s)\n", ivy_ast_node_type_to_string(node->n_type), b_string_ptr(str));
+	b_string_release(str);
+}
+
+static void init_state(struct parser_state *sp)
+{
+	struct unit_import_parser_state *state
+		= (struct unit_import_parser_state *)sp;
+	state->s_prev_token = IVY_KW_PACKAGE;
+}
+
+struct ast_node_type unit_import_node_ops = {
+	.n_add_child = add_child,
+        .n_print = print,
+	.n_init_state = init_state,
+	.n_state_size = sizeof(struct unit_import_parser_state),
+	.n_node_size = sizeof(struct ivy_ast_unit_import_node),
+	.n_symbol_parsers = {
+		[IVY_SYM_DOT] = parse_dot,
+	},
+	.n_token_parsers = {
+		[IVY_TOK_IDENT] = parse_ident,
+		[IVY_TOK_LINEFEED] = parse_linefeed,
+	}
+
+};
diff --git a/lang/ast/unit.c b/lang/ast/unit.c
index 18d8943..3dbf363 100644
--- a/lang/ast/unit.c
+++ b/lang/ast/unit.c
@@ -10,6 +10,13 @@ static enum ivy_status parse_package_keyword(
 	return IVY_OK;
 }
 
+static enum ivy_status parse_use_keyword(
+	struct ivy_parser *ctx, struct ivy_token *tok)
+{
+	parser_push_state(ctx, IVY_AST_UNIT_IMPORT);
+	return IVY_OK;
+}
+
 static enum ivy_status add_child(
 	struct ivy_ast_node *parent, struct ivy_ast_node *child)
 {
@@ -35,5 +42,6 @@ struct ast_node_type unit_node_ops = {
 	.n_node_size = sizeof(struct ivy_ast_unit_node),
         .n_keyword_parsers = {
 		[IVY_KW_PACKAGE] = parse_package_keyword,
+		[IVY_KW_USE] = parse_use_keyword,
 	},
 };
diff --git a/lang/include/ivy/lang/ast.h b/lang/include/ivy/lang/ast.h
index 119719a..acf9163 100644
--- a/lang/include/ivy/lang/ast.h
+++ b/lang/include/ivy/lang/ast.h
@@ -153,7 +153,7 @@ struct ivy_ast_unit_package_node {
 	b_queue n_ident;
 };
 
-struct ivy_ast_unit_use_node {
+struct ivy_ast_unit_import_node {
 	struct ivy_ast_node n_base;
 	/* queue of struct ivy_token; list of multi-part identifier parts. */
 	b_queue n_ident;