From 2e93df0fd85650728ce71389fd3ca018cb02cf08 Mon Sep 17 00:00:00 2001
From: Araozu <fernando@araozu.dev>
Date: Wed, 27 Mar 2024 08:18:31 -0500
Subject: [PATCH] scan datatypes

---
 lexer/identifier_lexer.test.ts |  7 +++++++
 lexer/identifier_lexer.ts      | 13 +++++++++++--
 lexer/lexer.ts                 | 15 ++++++++++++++-
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/lexer/identifier_lexer.test.ts b/lexer/identifier_lexer.test.ts
index 6016882..8e210f6 100644
--- a/lexer/identifier_lexer.test.ts
+++ b/lexer/identifier_lexer.test.ts
@@ -44,5 +44,12 @@ describe("Identifier Lexer", () => {
 
         expect(token).toEqual([{ v: "val", token_type: "keyword" }, 3]);
     });
+
+    test("should scan a datatype", () => {
+        const code = "Int";
+        const token = scan_identifier(code, 0, true);
+
+        expect(token).toEqual([{ v: "Int", token_type: "class-name" }, 3]);
+    });
 });
 
diff --git a/lexer/identifier_lexer.ts b/lexer/identifier_lexer.ts
index 086740e..29f34da 100644
--- a/lexer/identifier_lexer.ts
+++ b/lexer/identifier_lexer.ts
@@ -4,8 +4,12 @@ import { is_identifier_char } from "./utils.ts";
 /**
  * Scans an identifier, at the given position in the input string.
  * This function assumes that the character at the given position is a letter.
+ * 
+ * @param input the input string
+ * @param starting_position the position to start scanning from
+ * @param is_datatype whether the identifier is a datatype
  */
-export function scan_identifier(input: string, starting_position: number): [Token, number] {
+export function scan_identifier(input: string, starting_position: number, is_datatype = false): [Token, number] {
     let value = input[starting_position];
     let pos = starting_position + 1;
 
@@ -21,7 +25,12 @@ export function scan_identifier(input: string, starting_position: number): [Toke
         }
     }
 
-    return [{ v: value, token_type: check_keyword(value) }, pos];
+    if (is_datatype) {
+        return [{ v: value, token_type: "class-name" }, pos];
+    }
+    else {
+        return [{ v: value, token_type: check_keyword(value) }, pos];
+    }
 }
 
 function check_keyword(value: string): string {
diff --git a/lexer/lexer.ts b/lexer/lexer.ts
index a62cb57..ff1de07 100644
--- a/lexer/lexer.ts
+++ b/lexer/lexer.ts
@@ -1,6 +1,6 @@
 import { scan_identifier } from "./identifier_lexer.ts";
 import { scan_number } from "./number_lexer.ts";
-import { is_digit, is_lowercase } from "./utils.ts";
+import { is_digit, is_lowercase, is_uppercase } from "./utils.ts";
 
 export type Token = {
     v: string,
@@ -65,6 +65,19 @@ export function lex(code: string): Array<Token> {
             tokens.push(token);
             continue;
         }
+        // try to scan a datatype
+        else if (is_uppercase(c)) {
+            // if the current default token is not empty, push it to the tokens array
+            if (current_default_token !== "") {
+                tokens.push({ v: current_default_token, token_type: "" });
+                current_default_token = "";
+            }
+
+            const [token, next] = scan_identifier(code, current_pos, true);
+            current_pos = next;
+            tokens.push(token);
+            continue;
+        }
 
         // here, check if a token was found
         if (next_token !== null && next_position !== null) {