Hi Nicolai, On Sun, Jan 10, 2016 at 3:16 AM, Nicolai Hess <nicolaihess@gmail.com> wrote:
pharo fogbugz issue: 17359 MessageNotUnderstood: receiver of "keywords" is nil
is this valid pragma syntax:
<apicall: bool 'SetCursorPos' (long long) module: 'user32.dll'>
As others have said this is not a valid pragma. A valid pragma is a message expression (a message with no receiver) that has only literal arguments. There is one exception, to accept a variable name for the error code in a primitive invocation. And as Levente has said it is a goal of the new FFI to get rid of the old syntax you show above. And as Igor Stasenko discovered /any/ C signature can be written as a literal Array, providing we allow underscores in Symbols (which is a preference). So for example, the heapsort declaration from the standard C library: int heapsort(void *base, size_t nel, size_t width, int (*compar)(const void *, const void *)) could be written as a pragma via e.g. <ffiCCall: #(int heapsort(void *base, size_t nel, size_t width, int (*compar)(const void *, const void *)))> in which case it is equal to <ffiCCall: #(#int #heapsort #( #void #* #base #, #size_t #nel #, #size_t #width #, #int #( #* #compar ) #( #const #void #*, #const #void #*)))> which, while a massive hack, is pretty neat. The only difficulty in parsing the above s that void *, is #void #*, not #void #* #,. So for me, the natural pragma syntax for the new FFI should be a single keyword starting with ffi that includes the language with which to parse the pragma's argument, followed by a literal Array containing the signature (rather than e.g. a String). I'd also provide a special-purpose pretty-printer for literal arrays that would be used to pretty-print the above, e.g. when decompiling. This would easily allow extensions such as <ffiCcall: #(wchar_t * wcschr(const wchar_t *s, wchar_t c)) arg1is: #UnicodeString arg2is: Character> to guide a marshalling engine in providing automatic checks and conversions. [Slightly OT] Note that I'm already using this syntax in Alien callbacks because one thing it does is to normalize the signature, eliminating the significance of most whitespace (the #*, above being one example where it fails). So a Callback for heapsort above looks like voidstarvoidstarRetint: callbackContext sp: spAlien <signature: #(int (*)(const void *, const void *)) abi: #IA32> ^callbackContext wordResult: (block value: (Alien forPointer: (spAlien unsignedLongAt: 1)) value: (Alien forPointer: (spAlien unsignedLongAt: 5))) or voidstarvoidstarRetintARM32: callbackContext sp: spAlien <signature: #(int (*)(const void *, const void *)) abi: #ARM32> ^callbackContext wordResult: (block value: (Alien forPointer: (spAlien registerAt: 1)) value: (Alien forPointer: (spAlien registerAt: 2))) Hmmm, if Callback had subclasses for each ABI then the above would become IA32Callback methods for signature voidstarvoidstarRetint: callbackContext sp: spAlien <signature: #(int (*)(const void *, const void *))> ^callbackContext wordResult: (block value: (Alien forPointer: (spAlien unsignedLongAt: 1)) value: (Alien forPointer: (spAlien unsignedLongAt: 5))) ARM32Callback methods for signatures voidstarvoidstarRetint: callbackContext sp: spAlien <signature: #(int (*)(const void *, const void *))> ^callbackContext wordResult: (block value: (Alien forPointer: (spAlien registerAt: 1)) value: (Alien forPointer: (spAlien registerAt: 2))) Much nicer. I shall make it so. our (pharo) parser can not parse this (does not recognizes the
"selector parts" (apicall:module:) right)
Any recommendations how to fix this - fix RBParser or - change this pragma, for example, like this <apicall: #(bool SetCursorPos (long long)) module: 'user32.dll'>
nicolai
_,,,^..^,,,_ best, Eliot