From 5e1e8ed34a46738dda507a4a0f4e73065be74e57 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Fri, 29 Dec 2017 00:56:36 +0300
Subject: Lexer scaffold

---
 src/lexer.rs        | 10 ++++++++++
 src/lib.rs          | 15 ++++++++-------
 src/syntax_kinds.rs | 16 ++++++++++++++++
 src/text.rs         | 32 ++++++++++++++++++++++++++++++++
 src/tree.rs         | 31 +++++++++++++++++++++++++++++++
 tests/lexer.rs      | 24 ++++++++++++++++++++----
 6 files changed, 117 insertions(+), 11 deletions(-)
 create mode 100644 src/lexer.rs
 create mode 100644 src/syntax_kinds.rs
 create mode 100644 src/text.rs
 create mode 100644 src/tree.rs

diff --git a/src/lexer.rs b/src/lexer.rs
new file mode 100644
index 000000000..cda9fe2b2
--- /dev/null
+++ b/src/lexer.rs
@@ -0,0 +1,10 @@
+use {Token, TextUnit};
+use syntax_kinds::*;
+
+pub fn next_token(text: &str) -> Token {
+    let c = text.chars().next().unwrap();
+    Token {
+        kind: IDENT,
+        len: TextUnit::len_of_char(c),
+    }
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 31e1bb209..4385c0325 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,8 @@
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
-}
+mod text;
+mod tree;
+mod lexer;
+
+pub mod syntax_kinds;
+pub use text::TextUnit;
+pub use tree::{SyntaxKind, Token};
+pub use lexer::next_token;
diff --git a/src/syntax_kinds.rs b/src/syntax_kinds.rs
new file mode 100644
index 000000000..18574b7f5
--- /dev/null
+++ b/src/syntax_kinds.rs
@@ -0,0 +1,16 @@
+use tree::{SyntaxKind, SyntaxInfo};
+
+pub const IDENT: SyntaxKind = SyntaxKind(1);
+pub const WHITESPACE: SyntaxKind = SyntaxKind(2);
+
+
+static IDENT_INFO: SyntaxInfo = SyntaxInfo {
+    name: "IDENT",
+};
+
+pub(crate) fn syntax_info(kind: SyntaxKind) -> &'static SyntaxInfo {
+    match kind {
+        IDENT => &IDENT_INFO,
+        _ => unreachable!(),
+    }
+}
\ No newline at end of file
diff --git a/src/text.rs b/src/text.rs
new file mode 100644
index 000000000..5297275ed
--- /dev/null
+++ b/src/text.rs
@@ -0,0 +1,32 @@
+use std::fmt;
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct TextUnit(u32);
+
+impl TextUnit {
+    pub fn len_of_char(c: char) -> TextUnit {
+        TextUnit(c.len_utf8() as u32)
+    }
+
+    pub fn new(val: u32) -> TextUnit {
+        TextUnit(val)
+    }
+}
+
+impl fmt::Debug for TextUnit {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        <Self as fmt::Display>::fmt(self, f)
+    }
+}
+
+impl fmt::Display for TextUnit {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl From<TextUnit> for u32 {
+    fn from(tu: TextUnit) -> u32 {
+        tu.0
+    }
+}
diff --git a/src/tree.rs b/src/tree.rs
new file mode 100644
index 000000000..0924f38d0
--- /dev/null
+++ b/src/tree.rs
@@ -0,0 +1,31 @@
+use text::{TextUnit};
+use syntax_kinds::syntax_info;
+
+use std::fmt;
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SyntaxKind(pub(crate) u32);
+
+impl SyntaxKind {
+    fn info(self) -> &'static SyntaxInfo {
+        syntax_info(self)
+    }
+}
+
+impl fmt::Debug for SyntaxKind {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let name = self.info().name;
+        f.write_str(name)
+    }
+}
+
+
+pub(crate) struct SyntaxInfo {
+    pub name: &'static str,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Token {
+    pub kind: SyntaxKind,
+    pub len: TextUnit,
+}
\ No newline at end of file
diff --git a/tests/lexer.rs b/tests/lexer.rs
index de76f0a15..a27e7c395 100644
--- a/tests/lexer.rs
+++ b/tests/lexer.rs
@@ -1,9 +1,13 @@
 extern crate file;
 #[macro_use(assert_diff)]
 extern crate difference;
+extern crate libsyntax2;
 
 use std::path::{PathBuf, Path};
 use std::fs::read_dir;
+use std::fmt::Write;
+
+use libsyntax2::{Token, next_token};
 
 #[test]
 fn lexer_tests() {
@@ -46,10 +50,22 @@ fn lexer_test_case(path: &Path) {
     )
 }
 
-fn tokenize(text: &str) -> Vec<()> {
-    Vec::new()
+fn tokenize(text: &str) -> Vec<Token> {
+    let mut text = text;
+    let mut acc = Vec::new();
+    while !text.is_empty() {
+        let token = next_token(text);
+        acc.push(token);
+        let len: u32 = token.len.into();
+        text = &text[len as usize..];
+    }
+    acc
 }
 
-fn dump_tokens(tokens: &[()]) -> String {
-    "IDENT 5\nKEYWORD 1\nIDENT 5\n".to_string()
+fn dump_tokens(tokens: &[Token]) -> String {
+    let mut acc = String::new();
+    for token in tokens {
+        write!(acc, "{:?} {}\n", token.kind, token.len).unwrap()
+    }
+    acc
 }
\ No newline at end of file
-- 
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