feat: lex datatype

build.zig

@@ -94,6 +94,7 @@ pub fn build(b: *std.Build) void {
         "src/01_lexic/root.zig",
         "src/01_lexic/number.zig",
         "src/01_lexic/identifier.zig",
+        "src/01_lexic/datatype.zig",
         "src/01_lexic/token.zig",
         "src/01_lexic/utils.zig",
     };

src/01_lexic/datatype.zig

@@ -0,0 +1,53 @@
+const std = @import("std");
+const token = @import("./token.zig");
+const utils = @import("./utils.zig");
+
+const Token = token.Token;
+const TokenType = token.TokenType;
+const LexError = token.LexError;
+const LexReturn = token.LexReturn;
+
+/// Lexes a Datatype
+pub fn lex(input: []const u8, start: usize) LexError!?LexReturn {
+    const cap = input.len;
+    var final_pos = start;
+
+    if (start >= cap) {
+        return null;
+    }
+
+    // lex uppercase
+    if (!utils.is_uppercase(input[start])) {
+        return null;
+    }
+    final_pos += 1;
+
+    // lex many lowercase/uppercase/underscore/number
+    if (utils.lex_many(utils.is_identifier_char, input, final_pos)) |new_pos| {
+        final_pos = new_pos;
+    }
+
+    return .{
+        Token.init(input[start..final_pos], TokenType.Identifier, start),
+        final_pos,
+    };
+}
+
+test "should lex datatype" {
+    const input = "MyType";
+    const output = try lex(input, 0);
+
+    if (output) |tuple| {
+        const t = tuple[0];
+        try std.testing.expectEqualDeep("MyType", t.value);
+    } else {
+        try std.testing.expect(false);
+    }
+}
+
+test "shouldnt lex identifier" {
+    const input = "myDatatype";
+    const output = try lex(input, 0);
+
+    try std.testing.expect(output == null);
+}

src/01_lexic/identifier.zig

@@ -7,6 +7,7 @@ const TokenType = token.TokenType;
 const LexError = token.LexError;
 const LexReturn = token.LexReturn;
 
+/// Lexes a datatype
 pub fn lex(input: []const u8, start: usize) LexError!?LexReturn {
     const cap = input.len;
     var final_pos = start;

src/01_lexic/root.zig

@@ -27,8 +27,6 @@ pub fn tokenize(input: []const u8, alloc: std.mem.Allocator) !void {
             break;
         }
     }
-
-    std.debug.print("array list len: {d}", .{tokens.items.len});
 }
 
 /// Ignores all whitespace on `input` since `start`

src/01_lexic/utils.zig

@@ -22,6 +22,10 @@ pub fn is_lowercase(c: u8) bool {
     return 'a' <= c and c <= 'z';
 }
 
+pub fn is_uppercase(c: u8) bool {
+    return 'A' <= c and c <= 'Z';
+}
+
 pub fn is_lowercase_underscore(c: u8) bool {
     return c == '_' or ('a' <= c and c <= 'z');
 }