bshell: implement bytecode generation for arithmetic expressions and if-statements

bshell/compile/expression.c

@@ -0,0 +1,72 @@
+#include "compile-node.h"
+
+static struct ast_iterate_result do_compile_node(
+	struct ast_node *node,
+	enum ast_iteration_type it_type,
+	struct ast_iterator *it,
+	struct compile_ctx *ctx)
+{
+	if (it_type != AST_ITERATION_POST) {
+		int flags = 0;
+		switch (node->n_type) {
+		case AST_BLOCK:
+			break;
+		default:
+			flags |= AST_ITERATE_ADD_CHILDREN;
+			break;
+		}
+
+		return AST_ITERATE_OK(flags);
+	}
+
+	ctx->c_depth = node->n_it.e_depth;
+	struct compile_state *state = compile_get_state(ctx);
+	while (state->s_depth >= ctx->c_depth && state->s_depth > 0) {
+		compile_pop_state(ctx);
+		state = compile_get_state(ctx);
+	}
+
+	compile_node_impl impl = NULL;
+
+	if (node->n_type < state->s_type->s_nr_compile_node) {
+		impl = state->s_type->s_compile_node[node->n_type];
+	}
+
+	if (!impl) {
+		impl = state->s_type->s_compile_node_generic;
+	}
+
+	if (!impl) {
+		return AST_ITERATE_OK(0);
+	}
+
+	struct compile_result result = impl(ctx, node);
+	unsigned int flags = 0;
+	if (result.r_flags & COMPILE_REPEAT_NODE) {
+		flags |= AST_ITERATE_REPEAT;
+	}
+
+	if (result.r_status == BSHELL_SUCCESS) {
+		return AST_ITERATE_OK(flags);
+	}
+
+	return AST_ITERATE_ERR(result.r_status);
+}
+
+enum bshell_status compile_expression(
+	struct compile_ctx *ctx,
+	struct ast_node *src)
+{
+	compile_push_state(ctx, COMPILE_NORMAL);
+
+	struct ast_iterator it = {0};
+	ast_node_iterate(src, &it, (ast_iterator_callback)do_compile_node, ctx);
+
+	struct compile_value *result = compile_pop_value(ctx);
+	if (result) {
+		compile_value_load(ctx, result);
+		compile_value_destroy(result);
+	}
+
+	return BSHELL_SUCCESS;
+}