organizize

crates/libsyntax2/src/lexer/ptr.rs

@@ -0,0 +1,74 @@
+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: 0.into(),
+        }
+    }
+
+    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 next_is(&self, c: char) -> bool {
+        self.next() == Some(c)
+    }
+
+    pub fn nnext_is(&self, c: char) -> bool {
+        self.nnext() == Some(c)
+    }
+
+    pub fn next_is_p<P: Fn(char) -> bool>(&self, p: P) -> bool {
+        self.next().map(p) == Some(true)
+    }
+
+    pub fn nnext_is_p<P: Fn(char) -> bool>(&self, p: P) -> bool {
+        self.nnext().map(p) == Some(true)
+    }
+
+    pub fn bump(&mut self) -> Option<char> {
+        let ch = self.chars().next()?;
+        self.len += TextUnit::of_char(ch);
+        Some(ch)
+    }
+
+    pub fn bump_while<F: Fn(char) -> bool>(&mut self, pred: F) {
+        loop {
+            match self.next() {
+                Some(c) if pred(c) => {
+                    self.bump();
+                }
+                _ => return,
+            }
+        }
+    }
+
+    pub fn current_token_text(&self) -> &str {
+        let len: u32 = self.len.into();
+        &self.text[..len as usize]
+    }
+
+    fn chars(&self) -> Chars {
+        let len: u32 = self.len.into();
+        self.text[len as usize..].chars()
+    }
+}