From ddc637c16120fb352183698f635fc93a68580f7b Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Sat, 30 Dec 2017 15:22:40 +0300
Subject: Lexer: start numbers

---
 src/lexer/mod.rs | 91 +++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 81 insertions(+), 10 deletions(-)

(limited to 'src/lexer/mod.rs')

diff --git a/src/lexer/mod.rs b/src/lexer/mod.rs
index 83a411cdd..afbbee4d0 100644
--- a/src/lexer/mod.rs
+++ b/src/lexer/mod.rs
@@ -22,16 +22,7 @@ fn next_token_inner(c: char, ptr: &mut Ptr) -> SyntaxKind {
     // They are not identifiers, and are handled further down.
     let ident_start = is_ident_start(c) && !string_literal_start(c, ptr.next(), ptr.nnext());
     if ident_start {
-        let is_single_letter = match ptr.next() {
-            None => true,
-            Some(c) if !is_ident_continue(c) => true,
-            _ => false,
-        };
-        if is_single_letter {
-            return if c == '_' { UNDERSCORE } else { IDENT };
-        }
-        ptr.bump_while(is_ident_continue);
-        return IDENT;
+        return scan_ident(c, ptr);
     }
 
     if is_whitespace(c) {
@@ -39,9 +30,89 @@ fn next_token_inner(c: char, ptr: &mut Ptr) -> SyntaxKind {
         return WHITESPACE;
     }
 
+    if is_dec_digit(c) {
+        return scan_number(c, ptr);
+    }
+
     ERROR
 }
 
+fn scan_ident(c: char, ptr: &mut Ptr) -> SyntaxKind {
+    let is_single_letter = match ptr.next() {
+        None => true,
+        Some(c) if !is_ident_continue(c) => true,
+        _ => false,
+    };
+    if is_single_letter {
+        return if c == '_' { UNDERSCORE } else { IDENT };
+    }
+    ptr.bump_while(is_ident_continue);
+    IDENT
+}
+
+fn scan_number(c: char, ptr: &mut Ptr) -> SyntaxKind {
+    if c == '0' {
+        match ptr.next().unwrap_or('\0') {
+            'b' | 'o' => {
+                ptr.bump();
+                scan_digits(ptr, false);
+            }
+            'x' => {
+                ptr.bump();
+                scan_digits(ptr, true);
+            }
+            '0'...'9' | '_' | '.' | 'e' | 'E' => {
+                scan_digits(ptr, true);
+            }
+            _ => return INT_NUMBER,
+        }
+    } else {
+        scan_digits(ptr, false);
+    }
+
+    // might be a float, but don't be greedy if this is actually an
+    // integer literal followed by field/method access or a range pattern
+    // (`0..2` and `12.foo()`)
+    if ptr.next_is('.') && !(ptr.nnext_is('.') || ptr.nnext_is_p(is_ident_start)) {
+        // might have stuff after the ., and if it does, it needs to start
+        // with a number
+        ptr.bump();
+        scan_digits(ptr, false);
+        scan_float_exponent(ptr);
+        return FLOAT_NUMBER;
+    }
+    // it might be a float if it has an exponent
+    if ptr.next_is('e') || ptr.next_is('E') {
+        scan_float_exponent(ptr);
+        return FLOAT_NUMBER;
+    }
+    INT_NUMBER
+}
+
+fn scan_digits(ptr: &mut Ptr, allow_hex: bool) {
+    while let Some(c) = ptr.next() {
+        match c {
+            '_' | '0'...'9' => {
+                ptr.bump();
+            }
+            'a'...'f' | 'A' ... 'F' if allow_hex => {
+                ptr.bump();
+            }
+            _ => return
+        }
+    }
+}
+
+fn scan_float_exponent(ptr: &mut Ptr) {
+    if ptr.next_is('e') || ptr.next_is('E') {
+        ptr.bump();
+        if ptr.next_is('-') || ptr.next_is('+') {
+            ptr.bump();
+        }
+        scan_digits(ptr, false);
+    }
+}
+
 fn string_literal_start(c: char, c1: Option<char>, c2: Option<char>) -> bool {
     match (c, c1, c2) {
         ('r', Some('"'), _) |
-- 
cgit v1.2.3