Initial attempt at ast builtin module

Author: windelbouwman

tests/snippets/ast_snippet.py

@@ -0,0 +1,9 @@
+
+import ast
+
+source = """
+def foo():
+    print('bar')
+"""
+n = ast.parse(source)
+print(n)

vm/src/stdlib/ast.rs

@@ -0,0 +1,70 @@
+/*
+ * Ast standard module
+ *
+ * This module makes use of the parser logic, and translates all ast nodes
+ * into python ast.AST objects.
+ */
+
+extern crate rustpython_parser;
+
+use self::rustpython_parser::{ast, parser};
+use super::super::obj::{objdict, objfloat, objint, objlist, objstr, objtuple, objtype};
+use super::super::objbool;
+use super::super::pyobject::{
+    DictProtocol, PyContext, PyFuncArgs, PyObjectKind, PyObjectRef, PyResult, TypeProtocol,
+};
+use super::super::VirtualMachine;
+
+fn program_to_ast(ctx: &PyContext, program: &ast::Program) -> PyObjectRef {
+    let mut body = vec![];
+    for statement in &program.statements {
+        body.push(statement_to_ast(ctx, statement));
+    }
+    // TODO: create Module node and set attributes:
+    let ast_node = ctx.new_list(body);
+    ast_node
+}
+
+fn statement_to_ast(ctx: &PyContext, statement: &ast::LocatedStatement) -> PyObjectRef {
+    match &statement.node {
+        ast::Statement::FunctionDef { name, args, body } => {
+            // TODO: create ast.FunctionDef object and set attributes
+            // let node = ctx.new_object();
+            let mut py_body = vec![];
+            py_body.push(ctx.new_str(format!("{:?}", name)));
+            // node.set_attr("name", new_str(name));
+            for statement in body {
+                py_body.push(statement_to_ast(ctx, statement));
+            }
+
+            ctx.new_list(py_body)
+        },
+        _ => {
+            ctx.new_str(format!("{:?}", statement))
+        }
+    }
+
+    // TODO: set lineno on object
+}
+
+fn ast_parse(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    arg_check!(vm, args, required = [(source, Some(vm.ctx.str_type()))]);
+
+    let source_string = objstr::get_value(source);
+    let internal_ast = match parser::parse_program(&source_string) {
+        Ok(ast) => ast,
+        Err(msg) => {
+            return Err(vm.new_value_error(msg));
+        }
+    };
+
+    // source.clone();
+    let ast_node = program_to_ast(&vm.ctx, &internal_ast);
+    Ok(ast_node)
+}
+
+pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
+    let ast_mod = ctx.new_module(&"ast".to_string(), ctx.new_scope(None));
+    ast_mod.set_item("parse", ctx.new_rustfunc(ast_parse));
+    ast_mod
+}

vm/src/stdlib/mod.rs

@@ -1,3 +1,4 @@
+mod ast;
 mod json;
 use std::collections::HashMap;
 
@@ -8,5 +9,6 @@ pub type StdlibInitFunc = fn(&PyContext) -> PyObjectRef;
 pub fn get_module_inits() -> HashMap<String, StdlibInitFunc> {
     let mut modules = HashMap::new();
     modules.insert("json".to_string(), json::mk_module as StdlibInitFunc);
+    modules.insert("ast".to_string(), ast::mk_module as StdlibInitFunc);
     modules
 }