qmake-ng

qmake-ng is a desperate attempt to write Qt qmake replacement. Development stack: D programming language + DUB + Pegged. Pegged is a parsing expression grammar (PEG) generator. To resolve qmake grammar ambiguity, custom preprocessor was written and used.

Status

Currently only lexer and parser were implemented. All Qt source project files are successfully parsed. So, qmake-ng can be useful at least as a strict linter for qmake project files.

Usage

# Parse project
qmake-ng myproject.pro

# Recursively parse all qmake projects in directory
qmake-ng ~/my/dir

Goals

• qmake parser silently skip some syntax errors (e.g.)
• qmake parser behavior is not obvious in complex scenario (e.g. white space between function name and parenthesis)
• qmake can only generate makefiles/etc, but cannot interpret project on-the-fly like qbs
• qmake source code heavily use Qt private infrastructure and cannot be easily fixed by stranger

Pegged usage allowed to make parser much more strict than the original one. E.g. original qmake just ignores extra closing parenthesis, but qmake-ng fails:

message(Hello))

Grammar ambiguity

There is no official qmake project grammar. So, i was forced to "restore" it using valid project examples. Something like Rosetta stone :D Moreover, qmake grammar is just ambiguous:

windows:x64:error("x86_64 still not supported")

Here the first colon means logical AND, but the last one separates scope condition from true-branch. Another example:

contains(CONFIG, ^(android)$)

Notice that second function argument is not enquoted. Parser must somehow detect whether argument is a regular expression and process it separately.

So one should understand - the current version of grammar cannot be proved to be complete. However, it already parsed all of Qt's itself project files (~5000). And i hope it cover the most of qmake syntax stuff.

Plans

• qmake project files parser/linter with AST generation (DONE)
• semantic analyzer using AST (TODO)
• built-in test and replace functions implementation
• qbs-like on-the-fly interpretation of project commands without makefiles generation (TODO)