Simple identifier lexer

1 files changed, 38 insertions, 0 deletions

diff --git a/src/lexer/ptr.rs b/src/lexer/ptr.rs
new file mode 100644
index 000000000..4638dac21
--- /dev/null
+++ b/src/lexer/ptr.rs
@@ -0,0 +1,38 @@
+use {TextUnit};
+
+use std::str::Chars;
+
+pub(crate) struct Ptr<'s> {
+    text: &'s str,
+    len: TextUnit,
+}
+
+impl<'s> Ptr<'s> {
+    pub fn new(text: &'s str) -> Ptr<'s> {
+        Ptr { text, len: TextUnit::new(0) }
+    }
+
+    pub fn into_len(self) -> TextUnit {
+        self.len
+    }
+
+    pub fn next(&self) -> Option<char> {
+        self.chars().next()
+    }
+
+    pub fn nnext(&self) -> Option<char> {
+        let mut chars = self.chars();
+        chars.next()?;
+        chars.next()
+    }
+
+    pub fn bump(&mut self) -> Option<char> {
+        let ch = self.chars().next()?;
+        self.len += TextUnit::len_of_char(ch);
+        Some(ch)
+    }
+
+    fn chars(&self) -> Chars {
+        self.text[self.len.0 as usize ..].chars()
+    }
+}