Make the regex cache work #56

src/mango/io/fortest/fromstr.rs

@@ -23,10 +23,10 @@ impl Reader for StringReader {
         false
     }
 
-    fn matches(&mut self, subpattern: String) -> Option<String> {
+    fn matches(&mut self, subpattern: &str) -> Option<String> {
         REXCACHE.with(|rl| {
             let mut rexlib = rl.borrow_mut();
-            //            let rex = rexlib.make_or_get(subpattern);
+            let rex = rexlib.make_or_get(subpattern);
         });
         Option::None // TODO
     }

src/mango/io/typ.rs

@@ -1,12 +1,10 @@
-use regex::Regex;
-
 /// A reader represents a source 'file', which may be a file, webpage, string, ...
 pub trait Reader {
     /// Checks whether the `text` is found starting from the current position.
     fn equals(&mut self, text: &str) -> bool;
 
     /// Checks whether the code from the current position matches a regex pattern.
-    fn matches(&mut self, subpattern: String) -> Option<String>;
+    fn matches(&mut self, subpattern: &str) -> Option<String>;
 }
 
 pub trait Writer {

src/mango/io/util.rs

@@ -1,3 +1,4 @@
+use regex::Error;
 use regex::Regex;
 use std::cell::RefCell;
 use std::collections::HashMap;
@@ -8,11 +9,19 @@ pub struct RegexCache {
 
 impl RegexCache {
     // Not public to prevent having more than one instance.
-    pub fn new() -> Self {
+    fn new() -> Self {
         RegexCache {
             cache: HashMap::new(),
         }
     }
+
+    pub fn make_or_get(&mut self, subpattern: &str) -> Result<&Regex, Error> {
+        if !self.cache.contains_key(subpattern) {
+            let regex = Regex::new(&format!("^ *{}", subpattern))?;
+            self.cache.insert(subpattern.to_owned(), regex);
+        }
+        Result::Ok(self.cache.get(subpattern).unwrap())
+    }
 }
 
 thread_local! {