IN: alien.syntax
-USING: alien alien.c-types alien.parser alien.libraries
-classes.struct help.markup help.syntax see ;
+USING: alien alien.c-types alien.enums alien.libraries classes.struct
+help.markup help.syntax see ;
HELP: DLL"
{ $syntax "DLL\" path\"" }
{ $notes "Logical library names are defined with the " { $link add-library } " word." } ;
HELP: FUNCTION:
-{ $syntax "FUNCTION: return name ( parameters ) ;" }
+{ $syntax "FUNCTION: return name ( parameters )" }
{ $values { "return" "a C return type" } { "name" "a C function name" } { "parameters" "a comma-separated sequence of type/name pairs; " { $snippet "type1 arg1, type2 arg2, ..." } } }
{ $description "Defines a new word " { $snippet "name" } " which calls the C library function with the same " { $snippet "name" } " in the logical library given by the most recent " { $link POSTPONE: LIBRARY: } " declaration."
$nl
}
"You can define a word for invoking it:"
{ $unchecked-example
- "LIBRARY: foo\nFUNCTION: void the_answer ( c-string question, int value ) ;"
+ "LIBRARY: foo\nFUNCTION: void the_answer ( c-string question, int value )"
"\"the question\" 42 the_answer"
"The answer to the question is 42."
} }
"Using the " { $link c-string } " type instead of " { $snippet "char*" } " causes the FFI to automatically convert Factor strings to C strings. See " { $link "c-strings" } " for more information on using strings with the FFI."
-{ $notes "Note that the parentheses and commas are only syntax sugar and can be omitted; they serve no purpose other than to make the declaration easier to read. The following definitions are equivalent:"
-{ $code
- "FUNCTION: void glHint ( GLenum target, GLenum mode ) ;"
- "FUNCTION: void glHint GLenum target GLenum mode ;"
-}
-"To make a Factor word with a name different from the C function, use " { $link POSTPONE: FUNCTION-ALIAS: } "." } ;
+{ $notes "To make a Factor word with a name different from the C function, use " { $link POSTPONE: FUNCTION-ALIAS: } "." } ;
HELP: FUNCTION-ALIAS:
{ $syntax "FUNCTION-ALIAS: factor-name
{ $notes "This word differs from " { $link typedef } " in that it runs at parse time, to ensure correct ordering of operations when loading source files. Words defined in source files are compiled before top-level forms are run, so if a source file defines C binding words and uses " { $link typedef } ", the type alias won't be available at compile time." } ;
HELP: ENUM:
-{ $syntax "ENUM: type/f words... ;" }
-{ $values { "type" "a name to typedef to int or f" } { "words" "a sequence of word names" } }
-{ $description "Creates a sequence of word definitions in the current vocabulary. Each word pushes an integer according to the rules of C enums." }
-{ $notes "This word emulates a C-style " { $snippet "enum" } " in Factor. While this feature can be used for any purpose, using integer constants is discouraged unless it is for interfacing with C libraries. Factor code should use " { $link "words.symbol" } " or " { $link "singletons" } " instead." }
+{ $syntax "ENUM: type words... ;" "ENUM: type < base-type words..." }
+{ $values { "type" { $maybe "a name to typedef to int" } } { "words" "a sequence of word names" } }
+{ $description "Creates a c-type that boxes and unboxes integer values to symbols. A singleton is defined for each member word which allows generic dispatch on the enum's members. The base c-type can optionally be specified and defaults to " { $link int } ". A constructor word " { $snippet "<type>" } " is defined for converting from integers to singletons. The generic word " { $link enum>number } " converts from singletons to integers. Enum-typed values are automatically prettyprinted as their singleton words. Unrecognizing enum numbers are kept as numbers." }
{ $examples
"Here is an example enumeration definition:"
{ $code "ENUM: color_t red { green 3 } blue ;" }
- "It is equivalent to the following series of definitions:"
- { $code "CONSTANT: red 0" "CONSTANT: green 3" "CONSTANT: blue 4" }
+ $nl
+ "The following expression returns true:"
+ { $code "3 <color_t> [ green = ] [ enum>number 3 = ] bi and" }
+ $nl
+ "Here is a version where the C-type takes a single byte:"
+ { $code "ENUM: tv_peripherals_1 < uchar"
+ "{ appletv 1 } { chromecast 2 } { roku 4 } ;"
+ }
+ $nl
+ "The same as above but four bytes instead of one:"
+ { $code "ENUM: tv_peripherals_4 < uint"
+ "{ appletv 1 } { chromecast 2 } { roku 4 } ;"
+ }
+ $nl
+ "We can define a generic and dispatch on it:"
+ { $code "ENUM: tv_peripherals_4 < uint"
+ "{ appletv 1 } { chromecast 2 } { roku 4 } ;"
+ ""
+ "GENERIC: watch-device ( device -- )"
+ "M: appletv watch-device drop \"watching appletv\" print ;"
+ "M: chromecast watch-device drop \"watching chromecast\" print ;"
+ ""
+ "appletv watch-device"
+ }
} ;
HELP: C-TYPE:
{ $syntax "C-TYPE: type" }
{ $values { "type" "a new C type" } }
-{ $description "Defines a new, opaque C type. Since it is opaque, " { $snippet "type" } " will not be directly usable as a parameter or return type of a " { $link POSTPONE: FUNCTION: } " or as a slot of a " { $link POSTPONE: STRUCT: } ". However, it can be used as the type of a " { $link pointer } "."
+{ $description "Defines a new, opaque C type. Since it is opaque, " { $snippet "type" } " will not be directly usable as a parameter or return type of a " { $link POSTPONE: FUNCTION: } " or as a slot of a " { $link POSTPONE: STRUCT: } ". However, it can be used as the type of a " { $link pointer } "." $nl
{ $snippet "C-TYPE:" } " can also be used to forward declare C types, allowing circular dependencies to occur between types. For example:"
-{ $code """C-TYPE: forward
+{ $code "C-TYPE: forward
STRUCT: backward { x forward* } ;
-STRUCT: forward { x backward* } ; """ } }
+STRUCT: forward { x backward* } ;" } }
{ $notes "Primitive C types are displayed using " { $snippet "C-TYPE:" } " syntax when they are " { $link see } "n." } ;
HELP: CALLBACK:
-{ $syntax "CALLBACK: return type ( parameters ) ;" }
+{ $syntax "CALLBACK: return type ( parameters )" }
{ $values { "return" "a C return type" } { "type" "a type name" } { "parameters" "a comma-separated sequence of type/name pairs; " { $snippet "type1 arg1, type2 arg2, ..." } } }
{ $description "Defines a new function pointer C type word " { $snippet "type" } ". The newly defined word works both as a C type and as a wrapper for " { $link alien-callback } " for callbacks that accept the given return type and parameters. The ABI of the callback is decided from the ABI of the active " { $link POSTPONE: LIBRARY: } " declaration." }
{ $examples
{ $code
- "CALLBACK: bool FakeCallback ( int message, void* payload ) ;"
+ "CALLBACK: bool FakeCallback ( int message, void* payload )"
": MyFakeCallback ( -- alien )"
" [| message payload |"
" \"message #\" write"
{ POSTPONE: TYPEDEF: typedef } related-words
-HELP: c-struct?
-{ $values { "c-type" "a C type" } { "?" "a boolean" } }
-{ $description "Tests if a C type is a structure defined by " { $link POSTPONE: STRUCT: } "." } ;
-
HELP: C-GLOBAL:
{ $syntax "C-GLOBAL: type name" }
{ $values { "type" "a C type" } { "name" "a C global variable name" } }
-{ $description "Defines a new word named " { $snippet "name" } " which accesses a global variable in the current library, set with " { $link POSTPONE: LIBRARY: } "." } ;
+{ $description "Defines a getter " { $snippet "name" } " and setter " { $snippet "set-name" } " for the global value in the current library, set with " { $link POSTPONE: LIBRARY: } "." } ;
+
+HELP: INITIALIZE-ALIEN:
+{ $syntax "INITIALIZE-ALIEN: type ... ;" }
+{ $description "Initializes a " { $snippet "type" } " using the provided definition." } ;
+
+ARTICLE: "alien.enums" "Enumeration types"
+"The " { $vocab-link "alien.enums" } " vocab contains the implementation for " { $link POSTPONE: ENUM: } " C types, and provides words for converting between enum singletons and integers. It is possible to dispatch off of members of an enum."
+$nl
+"Defining enums:"
+{ $subsection POSTPONE: ENUM: }
+"Defining enums at run-time:"
+{ $subsection define-enum }
+"Conversions between enums and integers:"
+{ $subsections enum>number number>enum } ;
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