[Andrew Gazelka (andrewgazelka)]

Motivation

This line fails with missing ; or newline:

Prefab mullion { (MadeOf, aluminium_6063)  Profile: {width_mm: 65, depth_mm: 200, wall_mm: 3} }

Nothing about it is ambiguous: the pair ends at ) and the next token can only start a new statement.

Rule

In flecs_script_stmt_w_separator, after a statement that is not followed by ;, a newline, } or the end of the script, the parser now accepts the next statement on the same line when both of these hold:

1. The previous statement's last token ends with ), } or ].
2. The next token is one of:
   • an identifier or a string;
   • a statement keyword: with module using template prop mut const export if for include fn await try continue async while;
   • (, but only when the previous statement ended with } or ].

Everything else still errors with missing ; or newline.

Restrictions that keep it unambiguous

• Only after a closing delimiter. After Foo or Mass: 10, an identifier could be part of the Kind name declaration or of an expression, so Foo Bar still declares entity Bar of kind Foo, and Foo Bar Baz, Mass: 10 Foo and const x = 10 Foo are still errors.
• No ( after ). (A, B) (C, D) and X(...) (...) read as an initializer, the same as with (A, B) (expr), so this stays an error.
• No { as the next statement. Position: {10, 20} {} reads like a second initializer or a scope, so it stays an error. Anonymous entities still need a separator.
• No @ annotations as the next statement. An annotation consumes the rest of its line, so it must start a line.
• A token that a statement consumes itself is never seen by this check. Examples are else and catch after }, and a { after (A, B) (a pair scope) or after Foo bar (an entity scope). Previously valid scripts therefore parse exactly as before; only inputs that used to be errors change.

Changes

• src/addons/script/parser.c: adds flecs_script_stmt_can_juxtapose, and flecs_script_stmt_w_separator calls it. The last token is found with the existing flecs_parser_stmt_end.
• distr/flecs.c: the same edit, applied verbatim.
• docs/FlecsScript.md: the Newlines section documents the rule.

Tests (test/script)

Four upstream Error tests asserted the old behaviour and are now valid input, so they were removed and replaced by Eval tests: missing_separator_between_components, missing_separator_between_component_and_tag, missing_separator_between_component_and_pair and missing_separator_after_scope.

New Eval tests (positive):

• 2_components_same_line_wo_semicolon: e { Position: {10, 20} Velocity: {1, 2} }
• component_and_tag_same_line_wo_semicolon: e { Position: {10, 20} Foo }
• component_and_pair_same_line_wo_semicolon: e { Position: {10, 20} (Likes, Apples) }
• pair_and_component_same_line_wo_semicolon (the motivating case): Prefab e { (Likes, Apples) Position: {x: 10, y: 20} }
• pair_and_child_same_line_wo_semicolon: e { (Likes, Apples) child { Foo } }
• 3_entities_same_line_wo_semicolon: a {} b { Foo } c {}
• kind_entity_after_scope_same_line_wo_semicolon: a { Foo } Prefab e { Position: {10, 20} }
• pair_after_scope_same_line_wo_semicolon: e { child {} (Likes, Apples) }
• const_after_pair_same_line_wo_semicolon: e { (Likes, Apples) const x = 10; Position: {$x, 20} }

New Error tests (must still fail with missing ; or newline):

• missing_separator_between_scalar_component_and_tag: e { Position: {10, 20}; Mass: 10 Foo }
• missing_separator_between_const_and_tag: e { const x = 10 Foo }
• missing_separator_between_tags_after_kind: e { Foo Bar Baz }
• missing_separator_between_pairs: e { (Likes, Apples) (Likes, Pears) }
• missing_separator_between_component_and_anonymous_entity: e { Position: {10, 20} {} }
• missing_separator_between_scope_and_annotation: e { Foo {} @brief hello }

missing_separator_between_const (const x = 10 const y = 20) is unchanged and still passes.

Results: the full script suite passes (8826 passed, 0 failed, IR disabled and enabled), built with CMake against the bake test driver. distr/flecs.c compiles with -Wall -Wextra -Werror.

[Andrew Gazelka (andrewgazelka)]

Superseded by the upstream PR SanderMertens#2379 (SanderMertens#2379).