From bccb6f3bf55ed0f1b32a1554d006873dff402a8d Mon Sep 17 00:00:00 2001
From: Windel Bouwman <windel@windel.nl>
Date: Sun, 14 Oct 2018 10:59:00 +0200
Subject: [PATCH] Add draft re module

---
 Cargo.lock                |  1 +
 tests/snippets/test_re.py |  8 +++++
 vm/Cargo.toml             |  1 +
 vm/src/stdlib/mod.rs      |  2 ++
 vm/src/stdlib/re.rs       | 61 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 73 insertions(+)
 create mode 100644 tests/snippets/test_re.py
 create mode 100644 vm/src/stdlib/re.rs

diff --git a/Cargo.lock b/Cargo.lock
index 98ab04562..ff07d7cae 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -474,6 +474,7 @@ dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustpython_parser 0.0.1",
  "serde 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/tests/snippets/test_re.py b/tests/snippets/test_re.py
new file mode 100644
index 000000000..24a2ee3b4
--- /dev/null
+++ b/tests/snippets/test_re.py
@@ -0,0 +1,8 @@
+
+import re
+
+haystack = "Hello world"
+needle = 'ello'
+
+print(re.search(needle, haystack))
+
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
index 74106dad5..5897d829e 100644
--- a/vm/Cargo.toml
+++ b/vm/Cargo.toml
@@ -11,3 +11,4 @@ serde = "1.0.66"
 serde_derive = "1.0.66"
 serde_json = "1.0.26"
 byteorder = "1.2.6"
+regex = "1"
diff --git a/vm/src/stdlib/mod.rs b/vm/src/stdlib/mod.rs
index 99b392d90..d1210cc99 100644
--- a/vm/src/stdlib/mod.rs
+++ b/vm/src/stdlib/mod.rs
@@ -4,6 +4,7 @@ mod json;
 mod keyword;
 mod math;
 mod pystruct;
+mod re;
 use std::collections::HashMap;
 
 use super::pyobject::{PyContext, PyObjectRef};
@@ -17,6 +18,7 @@ pub fn get_module_inits() -> HashMap<String, StdlibInitFunc> {
     modules.insert("ast".to_string(), ast::mk_module as StdlibInitFunc);
     modules.insert("keyword".to_string(), keyword::mk_module as StdlibInitFunc);
     modules.insert("math".to_string(), math::mk_module as StdlibInitFunc);
+    modules.insert("re".to_string(), re::mk_module as StdlibInitFunc);
     modules.insert("struct".to_string(), pystruct::mk_module as StdlibInitFunc);
     modules
 }
diff --git a/vm/src/stdlib/re.rs b/vm/src/stdlib/re.rs
new file mode 100644
index 000000000..3a53770c6
--- /dev/null
+++ b/vm/src/stdlib/re.rs
@@ -0,0 +1,61 @@
+/*
+ * Regular expressions.
+ *
+ * This module fits the python re interface onto the rust regular expression
+ * system.
+ */
+
+extern crate regex;
+use self::regex::Regex;
+
+use super::super::obj::{objstr, objtype};
+use super::super::pyobject::{
+    DictProtocol, PyContext, PyFuncArgs, PyObjectRef, PyResult, TypeProtocol,
+};
+use super::super::VirtualMachine;
+
+fn re_match(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    // TODO:
+    error!("TODO: implement match");
+    re_search(vm, args)
+}
+
+fn re_search(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    arg_check!(
+        vm,
+        args,
+        required = [
+            (pattern, Some(vm.ctx.str_type())),
+            (string, Some(vm.ctx.str_type()))
+        ]
+    );
+
+    let pattern_str = objstr::get_value(&pattern);
+    let search_text = objstr::get_value(&string);
+
+    match Regex::new(&pattern_str) {
+        Ok(regex) => {
+            // Now use regex to search:
+            match regex.find(&search_text) {
+                None => Ok(vm.get_none()),
+                Some(result) => {
+                    // Return match object:
+                    // TODO: implement match object
+                    // TODO: how to refer to match object defined in this
+                    // module?
+                    Ok(vm.ctx.new_str(result.as_str().to_string()))
+                }
+            }
+        }
+        Err(err) => Err(vm.new_value_error(format!("Error in regex: {:?}", err))),
+    }
+}
+
+pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
+    let py_mod = ctx.new_module(&"re".to_string(), ctx.new_scope(None));
+    let match_type = ctx.new_class(&"Match".to_string(), ctx.object());
+    py_mod.set_item("Match", match_type);
+    py_mod.set_item("match", ctx.new_rustfunc(re_match));
+    py_mod.set_item("search", ctx.new_rustfunc(re_search));
+    py_mod
+}