1 files changed, 28 insertions, 1 deletions
diff --git a/src/Lexer.zig b/src/Lexer.zig
index 3621a1c..62b2352 100644
--- a/src/Lexer.zig
+++ b/src/Lexer.zig
@@ -12,6 +12,10 @@ pub const Token = struct {
         minus,
         invalid,
         eof,
+        identifier,
+
+        // Keywords
+        @"if",
     };
 };
 
@@ -33,6 +37,11 @@ pub const Location = struct {
         }
         return value;
     }
+
+    /// Assumes that the location comes directly from an `identifier` token.
+    pub fn getIdent(self: Location, file_source: []const u8) []const u8 {
+        return file_source[self.start..self.end];
+    }
 };
 
 source: []const u8,
@@ -51,7 +60,10 @@ pub fn next(self: *Self) ?Token {
             self.start = self.pos;
             continue :s (self.eat() orelse return self.create(.eof));
         },
-        else => self.create(.invalid),
+        else => |c| if ('a' <= c and c <= 'z' or 'A' <= c and c <= 'Z')
+            self.identifierOrKeyword()
+        else
+            self.create(.invalid),
     };
 }
 
@@ -74,6 +86,21 @@ fn integerLiteral(self: *Self) Token {
         self.create(.invalid);
 }
 
+fn identifierOrKeyword(self: *Self) Token {
+    while (true) {
+        const c = self.peek() orelse 0;
+        if ('a' <= c and c <= 'z' or 'A' <= c and c <= 'Z' or c == '_') {
+            _ = self.eat();
+            continue;
+        }
+        const value = self.source[self.start..self.pos];
+        return self.create(switch (std.meta.stringToEnum(Token.Type, value) orelse .invalid) {
+            .@"if" => .@"if",
+            else => .identifier,
+        });
+    }
+}
+
 fn create(self: *Self, tajp: Token.Type) Token {
     const start = self.start;
     return .{ .loc = .{ .start = start, .end = self.pos }, .type = tajp };