![]() And if you try to trick the preprocessor by 'building' a new preprocessor directive through concatenation (and tricks like that), the behavior is. ![]() This means that you cant include a preprocessor directive into a macro replacement list. And also GTK whose macros are very readable. After the arguments for the invocation of a function-like macro have been identified, argument substitution takes place. C and C++ languages explicitly prohibit forming preprocessor directives as the result of macro expansion. a suitably configured recent GDB) are capable of macro expansion (thrn compile your C code with gcc -O0 -g3 -Wall) In Bismon, I use lots of quite long C macros. (cons (quote a) (append (list (quote b) (quote c)) (list (+ 1 2)))). ![]() Swift has two kinds of macros: freestanding macros, which appear on their own, without being attached to a declaration and attached macros, which modify the declaration of the program entity that follows them. define PREFIX foo // whatever RUNTEST(1) Explanation: From the C standard: 6.10.3.1 Argument substitution. The traditional Lisp macro expansion facility inhibits several important forms of. Macros transform one AST into another AST without depending on any external state, and without making changes to any external state. They should not be confused with C/C++ macros, which only carry through some kind of specialized string replacement, and are more akin to macros in languages such as Rust or Scala, although with their own particular twist. Swift macros work at the AST (abstract syntax tree) level to enable to generate code at compile time that is fed back to the compiler. The function-like macro declaration must not have any whitespace between the identifier and the first, opening, parenthesis. Macros aim to extend the capabilities of a programming language by introducing constructs similar to language primitives and eliminate as much boilerplate as possible. Introduced at WWDC 2023, Swift 5.9, now available in beta, brings a major extension to the language capabilities through support for generating code at compile-time using macros.
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