Lexer scaffold

5 files changed, 97 insertions, 7 deletions

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