Add support to _ in number literals

src/scanner.zig

@@ -253,20 +253,34 @@ pub const Scanner = struct {
     }
 
     fn number(self: *Self) !Token {
-        while (isNumber(self.peek())) {
+        var peeked: u8 = self.peek();
+        while (isNumber(peeked) or peeked == '_') {
             _ = self.advance();
+
+            peeked = self.peek();
+        }
+
+        if (self.source[self.current.offset - 1] == '_') {
+            return self.makeToken(.Error, "'_' must be between digits", null, null);
         }
 
         var is_float: bool = false;
         if (self.peek() == '.' and isNumber(self.peekNext())) {
             is_float = true;
             _ = self.advance(); // Consume .
 
-            while (isNumber(self.peek())) {
+            peeked = self.peek();
+            while (isNumber(peeked) or peeked == '_') {
                 _ = self.advance();
+
+                peeked = self.peek();
             }
         }
 
+        if (self.source[self.current.offset - 1] == '_') {
+            return self.makeToken(.Error, "'_' must be between digits", null, null);
+        }
+
         const float = if (is_float)
             std.fmt.parseFloat(f64, self.source[self.current.start..self.current.offset]) catch {
                 return self.makeToken(
@@ -337,12 +351,20 @@ pub const Scanner = struct {
 
     fn binary(self: *Self) Token {
         var peeked: u8 = self.peek();
-        while (peeked == '0' or peeked == '1') {
+        if (peeked == '_') {
+            return self.makeToken(.Error, "'_' must be between digits", null, null);
+        }
+
+        while (peeked == '0' or peeked == '1' or peeked == '_') {
             _ = self.advance();
 
             peeked = self.peek();
         }
 
+        if (self.source[self.current.offset - 1] == '_') {
+            return self.makeToken(.Error, "'_' must be between digits", null, null);
+        }
+
         return self.makeToken(
             .IntegerValue,
             null,
@@ -359,15 +381,22 @@ pub const Scanner = struct {
     }
 
     fn hexa(self: *Self) Token {
-        _ = self.advance(); // Consume 'x'
+        if (self.peek() == '_') {
+            return self.makeToken(.Error, "'_' must be between digits", null, null);
+        }
 
+        _ = self.advance(); // Consume 'x'
         var peeked: u8 = self.peek();
-        while (isNumber(peeked) or (peeked >= 'A' and peeked <= 'F') or (peeked >= 'a' and peeked <= 'f')) {
+        while (isNumber(peeked) or (peeked >= 'A' and peeked <= 'F') or (peeked >= 'a' and peeked <= 'f') or peeked == '_') {
             _ = self.advance();
 
             peeked = self.peek();
         }
 
+        if (self.source[self.current.offset - 1] == '_') {
+            return self.makeToken(.Error, "'_' must be between digits", null, null);
+        }
+
         return self.makeToken(
             .IntegerValue,
             null,

tests/001-basic-types.buzz

@@ -7,6 +7,24 @@ test "Basic types" {
     bool _ = true;
 }
 
+test "Underscore on number literals" {
+    int a = 100_000;
+
+    assert(a == 100000, message: "Could use an underscore on an int");
+
+    float b = 3.1_4;
+
+    assert(b == 3.14, message: "Could use an underscore on a float");
+
+    int bin = 0b1_0001;
+
+    assert(bin == 17, message: "Clould use an underscore on a binary int");
+
+    int h = 0xF_FFF;
+
+    assert(h == 65535, message: "Clould use an underscore on a hex int");
+}
+
 test "Char literal" {
     int char = 'A';
 
@@ -19,4 +37,4 @@ test "Char literal" {
     int slash = '\\';
 
     assert(slash == 92, message: "Could escape \\ in char literal");
-}
+}

tests/compile_errors/017-invalid-int-literal.buzz

@@ -0,0 +1,4 @@
+| '_' must be between digits
+test "invalid literals" {
+   int a = 100_;
+}

tests/compile_errors/018-invalid-float-literal.buzz

@@ -0,0 +1,4 @@
+| '_' must be between digits
+test "invalid literals" {
+   int a = 100.2_;
+}

tests/compile_errors/019-invalid-int-hex-literal.buzz

@@ -0,0 +1,4 @@
+| '_' must be between digits
+test "invalid hex literal" {
+   int a = 0x_100;
+}

tests/compile_errors/020-invalid-int-bin-literal.buzz

@@ -0,0 +1,4 @@
+| '_' must be between digits
+test "invalid bin literal" {
+   int a = 0b_100;
+}