feat: execute fixed arrays and indexed access

source/lexer/scan.hon

@@ -32,6 +32,7 @@ keywords strmap.StaticStringMap(TokenKind) :: strmap.init([
     { "false", .false },
     { "and", .and },
     { "or", .or },
+    { "mut", .mut },
 ])
 
 #! owns token storage and retains its allocator; release with deinit.

source/lexer/scan.test.hon

@@ -122,3 +122,22 @@ scans_ranges_without_consuming_float_dots test {
     try testing.expect_equal(u32(10), state.tokens.items[4].span.end)
     try testing.expect_equal(2, diagnostics.count(&diagnostic_store))
 }
+
+scans_array_delimiters_and_mut_keyword test {
+    strpool.strings = strpool.init(mem.c_allocator)
+    defer strpool.deinit(&strpool.strings)
+    diagnostic_store := diagnostics.init(mem.c_allocator)
+    defer diagnostics.deinit(&diagnostic_store)
+    state := init(mem.c_allocator)
+    defer deinit(&state)
+    try scan(&state, "[_]mut [2]i64 [1,2] [] mutable mut_1", &diagnostic_store)
+    expected [18]TokenKind :: [
+        .open_bracket, .ident, .close_bracket, .mut,
+        .open_bracket, .int, .close_bracket, .ident,
+        .open_bracket, .int, .comma, .int, .close_bracket,
+        .open_bracket, .close_bracket, .ident, .ident, .eof,
+    ]
+    try testing.expect_equal(expected.len, state.tokens.items.len)
+    for (expected) |kind, index| try testing.expect_equal(kind, state.tokens.items[index].kind)
+    try testing.expect_equal(0, diagnostics.count(&diagnostic_store))
+}

source/lexer/token.hon

@@ -24,6 +24,7 @@ TokenKind :: enum {
     break, continue
     true, false
     and, or
+    mut
 
     # literals
     ident, string