C preprocessing without braces

Preprocessor sigils emit directives for the C preprocessor; NanoC never evaluates their conditions. Indentation closes conditional chains with endif, with no C braces. A lone colon is exclusively a preprocessor else. Runtime else uses the word else.

NanoC

+ <stdio.h>
?+ _WIN32
  $ PLATFORM = "Windows"
:# defined(__linux__)
  $ PLATFORM = "Linux"
:
  $ PLATFORM = "Other"
f main()
  puts(PLATFORM)
  < 0

#include <stdio.h>
#ifdef _WIN32
#define PLATFORM "Windows"
#elif defined(__linux__)
#define PLATFORM "Linux"
#else
#define PLATFORM "Other"
#endif

int main(void) {
    puts(PLATFORM);
    return 0;
}

Syntax	C directive
`?+ NAME`	ifdef NAME
`?- NAME`	ifndef NAME
`?# expression`	if expression
`:# expression`	elif expression
`:`	else in a preprocessor chain
Dedent after a chain	endif
`$ NAME = replacement`	define NAME replacement
`$ NAME(args) = replacement`	Function-like define; keep NAME and ( adjacent
`$- NAME`	undef NAME
`+ <header.h>` / `+ "local.h"`	include
`!! "message"`	error; adjacent exclamation marks and a string literal
`$! payload`	pragma payload; support depends on the C compiler

Conditions can nest at file scope or inside functions, mixing with runtime blocks. Declarations may differ between configurations. Directive ordering, # stringification and ## token pasting are retained. Use raw C for multiline replacement lists, unusual include operands or configurations with different brace structure. Test each configuration you ship. NanoC expands macros and TT in every preprocessor branch, even ?# 0, before the C preprocessor runs. Use C macros for C-configuration-dependent definitions.