conlang 0.3.0: Total grammar overhaul

- Rewrote the grammar
- Rewrote the AST
- Rewrote the Parser
- Removed pretty printer (now handled by ast::ast_impl::Pretty, a Writer wrapper)
- Added items, and new keywords to go with them
  - Syntax is ~maybe temporary, based on Rust syntax

libconlang/src/token/token_type.rs

@@ -78,6 +78,7 @@ pub enum Type {
 pub enum Keyword {
     Break,
     Cl,
+    Const,
     Continue,
     Else,
     Enum,
@@ -85,13 +86,16 @@ pub enum Keyword {
     For,
     Fn,
     If,
+    Impl,
     In,
     Let,
     Mod,
     Mut,
+    Pub,
     Return,
     SelfKw,
     SelfTy,
+    Static,
     Struct,
     Super,
     True,
@@ -172,6 +176,7 @@ impl Display for Keyword {
         match self {
             Self::Break => "break".fmt(f),
             Self::Cl => "cl".fmt(f),
+            Self::Const => "const".fmt(f),
             Self::Continue => "continue".fmt(f),
             Self::Else => "else".fmt(f),
             Self::Enum => "enum".fmt(f),
@@ -179,13 +184,16 @@ impl Display for Keyword {
             Self::For => "for".fmt(f),
             Self::Fn => "fn".fmt(f),
             Self::If => "if".fmt(f),
+            Self::Impl => "impl".fmt(f),
             Self::In => "in".fmt(f),
             Self::Let => "let".fmt(f),
             Self::Mod => "mod".fmt(f),
             Self::Mut => "mut".fmt(f),
+            Self::Pub => "pub".fmt(f),
             Self::Return => "return".fmt(f),
             Self::SelfKw => "self".fmt(f),
             Self::SelfTy => "Self".fmt(f),
+            Self::Static => "static".fmt(f),
             Self::Struct => "struct".fmt(f),
             Self::Super => "super".fmt(f),
             Self::True => "true".fmt(f),
@@ -200,6 +208,7 @@ impl FromStr for Keyword {
         Ok(match s {
             "break" => Self::Break,
             "cl" => Self::Cl,
+            "const" => Self::Const,
             "continue" => Self::Continue,
             "else" => Self::Else,
             "enum" => Self::Enum,
@@ -207,13 +216,16 @@ impl FromStr for Keyword {
             "for" => Self::For,
             "fn" => Self::Fn,
             "if" => Self::If,
+            "impl" => Self::Impl,
             "in" => Self::In,
             "let" => Self::Let,
             "mod" => Self::Mod,
             "mut" => Self::Mut,
+            "pub" => Self::Pub,
             "return" => Self::Return,
             "self" => Self::SelfKw,
             "Self" => Self::SelfTy,
+            "static" => Self::Static,
             "struct" => Self::Struct,
             "super" => Self::Super,
             "true" => Self::True,