From 251ce4e66ec4cd14c2c9dac73cd0f8b0868c7232 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Mon, 23 Apr 2018 14:46:54 -0700
Subject: [PATCH] Start the interpreter code. Construct a basic scaffold.

---
 CMakeLists.txt        |   2 +-
 include/interpreter.h |  21 ++++++++
 src/interpreter.c     | 115 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 137 insertions(+), 1 deletion(-)
 create mode 100644 include/interpreter.h
 create mode 100644 src/interpreter.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c113045..b8bf799 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,7 @@ project(libabacus)
 
 add_compile_options(-pedantic -Wall)
 
-add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c src/trie.c src/refcount.c src/ref_vec.c src/ref_trie.c src/basetype.c src/value.c src/custom.c)
+add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c src/trie.c src/refcount.c src/ref_vec.c src/ref_trie.c src/basetype.c src/value.c src/custom.c src/interpreter.c)
 add_executable(libabacus src/main.c)
 add_subdirectory(external/liblex)
 
diff --git a/include/interpreter.h b/include/interpreter.h
new file mode 100644
index 0000000..299deb6
--- /dev/null
+++ b/include/interpreter.h
@@ -0,0 +1,21 @@
+#ifndef LIBABACUS_INTERPRETER_H
+#define LIBABACUS_INTERPRETER_H
+
+#include "table.h"
+#include "number.h"
+#include "tree.h"
+
+struct libab_interpreter_s {
+    libab_table* base_table;   
+    libab_number_impl* impl;
+};
+
+typedef struct libab_interpreter_s libab_interpreter;
+
+void libab_interpreter_init(libab_interpreter* intr,
+                            libab_table* table, libab_number_impl* impl);
+libab_result libab_interpreter_run(libab_interpreter* intr,
+                                   libab_tree* tree, libab_ref* into);
+void libab_interpreter_free(libab_interpreter* intr);
+
+#endif
diff --git a/src/interpreter.c b/src/interpreter.c
new file mode 100644
index 0000000..41f7660
--- /dev/null
+++ b/src/interpreter.c
@@ -0,0 +1,115 @@
+#include "interpreter.h"
+#include "util.h"
+
+void libab_interpreter_init(libab_interpreter* intr,
+                            libab_table* table, libab_number_impl* impl) {
+    intr->base_table = table;
+    intr->impl = impl;
+}
+
+struct interpreter_state {
+    libab_table* base_table;
+    libab_number_impl* impl;
+    libab_ref num_ref;
+};
+
+libab_result _interpreter_init(struct interpreter_state* state, libab_interpreter* intr) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_basetype* num_type;
+    state->base_table = intr->base_table;
+    state->impl = intr->impl;
+    libab_ref_null(&state->num_ref);
+
+    num_type = libab_table_search_basetype(state->base_table, "num");
+    if(num_type != NULL) {
+        libab_ref_free(&state->num_ref);
+        result = libab_instantiate_basetype(num_type, &state->num_ref, 0);
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        libab_ref_free(&state->num_ref);
+    }
+
+    return result;
+}
+
+void _interpreter_free(struct interpreter_state* state) {
+    libab_ref_free(&state->num_ref);
+}
+
+void _free_table(void* data) {
+    libab_table_free(data);
+    free(data);
+}
+
+libab_result _make_scope(libab_ref* into, libab_ref* parent) {
+    libab_table* table;
+    libab_result result = LIBAB_SUCCESS;
+    if((table = malloc(sizeof(*table)))) {
+        libab_table_init(table);
+        result = libab_ref_new(into, table, _free_table);
+
+        if(result != LIBAB_SUCCESS) {
+            _free_table(table);
+        }
+    } else {
+        result = LIBAB_MALLOC;
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        libab_ref_null(into);
+    }
+
+    return result;
+}
+
+libab_result _interpreter_run(struct interpreter_state* state,
+                                    libab_tree* tree, libab_ref* into, 
+                                    libab_ref* scope, int force_scope) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_ref new_scope;
+    int needs_scope = libab_tree_has_scope(tree->variant) || force_scope;
+    
+    if(needs_scope) {
+        result = _make_scope(&new_scope, scope);
+        scope = &new_scope;
+    }
+
+    if(result != LIBAB_SUCCESS) {
+
+    } else if(tree->variant == TREE_BASE || tree->variant == TREE_BLOCK) {
+        size_t index = 0;
+        libab_ref_null(into);
+        while(result == LIBAB_SUCCESS && index < tree->children.size) {
+            libab_ref_free(into);
+            result = _interpreter_run(state, vec_index(&tree->children, index), into, scope, 0);
+        }
+    }
+
+    if(needs_scope) {
+        libab_ref_free(&new_scope);
+    }
+
+    return result;
+}
+
+libab_result libab_interpreter_run(libab_interpreter* intr,
+                                   libab_tree* tree, libab_ref* into) {
+    struct interpreter_state state;
+    libab_result result = _interpreter_init(&state, intr);
+
+    if(result == LIBAB_SUCCESS) {
+        result = _interpreter_run(&state, tree, into, NULL, 1);
+        if(result != LIBAB_SUCCESS) {
+            _interpreter_free(&state);
+        }
+    } else {
+        libab_ref_null(into);
+    }
+
+    return result;
+}
+
+void libab_interpreter_free(libab_interpreter* intr) {
+    
+}