Use TryFrom<&str> for Tokens

Cargo.lock

@@ -836,8 +836,6 @@ dependencies = [
  "ena",
  "failure",
  "itertools",
- "lazy_static 1.4.0",
- "maplit",
  "radix_trie",
  "schala-lang-codegen",
  "schala-repl",

schala-lang/language/Cargo.toml

@@ -8,8 +8,6 @@ resolver = "2"
 [dependencies]
 itertools = "0.10"
 take_mut = "0.2.2"
-maplit = "1.0.1"
-lazy_static = "1.3.0"
 failure = "0.1.5"
 ena = "0.11.0"
 stopwatch = "0.0.7"

schala-lang/language/src/lib.rs

@@ -6,10 +6,6 @@
 //! It defines the `Schala` type, which contains the state for a Schala REPL, and implements
 //! `ProgrammingLanguageInterface` and the chain of compiler passes for it.
 
-#[macro_use]
-extern crate lazy_static;
-#[macro_use]
-extern crate maplit;
 extern crate schala_repl;
 #[macro_use]
 extern crate schala_lang_codegen;

schala-lang/language/src/tokenizing.rs

@@ -1,8 +1,5 @@
 use itertools::Itertools;
-use std::collections::HashMap;
-use std::rc::Rc;
-use std::iter::{Iterator, Peekable};
-use std::fmt;
+use std::{iter::{Iterator, Peekable}, convert::TryFrom, rc::Rc, fmt};
 
 use crate::source_map::Location;
 
@@ -63,9 +60,11 @@ pub enum Kw {
   Module, Import
 }
 
-lazy_static! {
-  static ref KEYWORDS: HashMap<&'static str, Kw> =
-    hashmap! {
+impl TryFrom<&str> for Kw {
+  type Error = ();
+
+  fn try_from(value: &str) -> Result<Self, Self::Error> {
+    Ok(match value {
       "if" => Kw::If,
       "then" => Kw::Then,
       "else" => Kw::Else,
@@ -88,7 +87,9 @@ lazy_static! {
       "false" => Kw::False,
       "module" => Kw::Module,
       "import" => Kw::Import,
-    };
+      _ => return Err(()),
+    })
+  }
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -239,9 +240,9 @@ fn handle_alphabetic(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>
     }
   }
 
-  match KEYWORDS.get(buf.as_str()) {
-    Some(kw) => TokenKind::Keyword(*kw),
-    None => TokenKind::Identifier(Rc::new(buf)),
+  match Kw::try_from(buf.as_str()) {
+    Ok(kw) => TokenKind::Keyword(kw),
+    Err(()) => TokenKind::Identifier(Rc::new(buf)),
   }
 }