Add Lua function call syntactic sugar and improve parser robustness

[davydog187]

Summary

This PR enhances the Lua parser with three major improvements to support more idiomatic Lua 5.3 syntax patterns. All changes include comprehensive unit tests.

Changes

1. Function Call Syntactic Sugar

Implements Lua's syntactic sugar for function calls without parentheses:

• func "string" → func("string")
• func{table} → func({table})
• Works for both regular function calls and method calls

Examples:

require "debug"           -- instead of require("debug")
print{1, 2, 3}           -- instead of print({1, 2, 3})
obj:method "str"         -- instead of obj:method("str")
config{debug = true}     -- instead of config({debug = true})

2. Empty Statement Support

The parser now correctly handles semicolons as empty statements:

• Multiple consecutive semicolons: ;;; print "test" ;;
• Semicolons after comments
• Semicolons at start of code, between statements, and in blocks
• Empty programs consisting only of semicolons

3. Comments in Expressions

The parser now skips comments that appear within expressions:

return x ~= -- force SETLINE before nil
nil

This enables more idiomatic Lua code with inline documentation.

Implementation Details

Parser modifications:

• Modified parse_block_acc to skip semicolons at the block level
• Removed recursive semicolon handling from parse_stmt_inner to avoid infinite recursion
• Added comment skipping to parse_prefix for expression-level comments
• Enhanced parse_infix to recognize string/table tokens after function names
• Updated method call parsing to support syntactic sugar patterns

Test coverage:

• 5 tests for function call syntactic sugar (test/lua/parser/expr_test.exs)
• 4 tests for comments in expressions (test/lua/parser/expr_test.exs)
• 8 tests for empty statements (test/lua/parser/statement_test.exs)

Testing

All 1120 tests pass, including 17 new parser tests.

mix test
# 50 doctests, 14 properties, 1120 tests, 0 failures

The Lua 5.3 test suite's constructs.lua file now parses successfully (it fails at runtime due to missing the debug module, which is expected).

Related

This builds on the work from #132 (load function implementation) and improves parser compatibility with the Lua 5.3 test suite.

🤖 Generated with Claude Code