Command: variant

Name:
variant - return specific variant of function
Synopsis:
funcname signature variant -> anytype true false
Description:
The operator variant checks whether a variant of the function matching a particular signature is available. If so, this variant and the value true are returned. If not, the return value is false. If the literal specifying the function does not refer to a trie the function has only a single variant and no information about the signature. In this case, the unique variant is returned. The operator variant can be used to optimize SLI code for speed in situations where it is guaranteed that a particular variant of a function is needed. Here, replacing the overloaded function by the specific variant removes the overhead of type checking. A typical situation in which the data types of the arguments are known is a function call inside a function with a specified signature (see example below). Another situation is machine generated SLI code where the machine, for example a compiler, is requested to emit optimized code restricted to particular data type. /incr [/doubletype] { 1.0 add } << /add /add [/doubletype /doubletype] variant pop >> Inline def
Parameters:
funcname, is a literal specifying the name of the function. Usually the literal refers to a trie with several variants. signature, is an array of literals defining the signature of the variant searched for
Examples:
/add [/doubletype /doubletype] variant pop --> /add_dd load /add [/doubletype /stringtype] variant --> false /add [/stringtype /doubletype] variant --> false /ArrayQ [/anytype] variant pop --> false /f {(hello) ==} def /f [/integertype] variant pop --> {(hello) ==}
Author:
Diesmann
FirstVersion:
090201
SeeAlso: Inline CompileMath def addtotrie cva

Source:
/home/abuild/rpmbuild/BUILD/nest-2.4.1/lib/sli/typeinit.sli

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Name:	variant - return specific variant of function
Synopsis:	funcname signature variant -> anytype true false
Description:	The operator variant checks whether a variant of the function matching a particular signature is available. If so, this variant and the value true are returned. If not, the return value is false. If the literal specifying the function does not refer to a trie the function has only a single variant and no information about the signature. In this case, the unique variant is returned. The operator variant can be used to optimize SLI code for speed in situations where it is guaranteed that a particular variant of a function is needed. Here, replacing the overloaded function by the specific variant removes the overhead of type checking. A typical situation in which the data types of the arguments are known is a function call inside a function with a specified signature (see example below). Another situation is machine generated SLI code where the machine, for example a compiler, is requested to emit optimized code restricted to particular data type. /incr [/doubletype] { 1.0 add } << /add /add [/doubletype /doubletype] variant pop >> Inline def
Parameters:	funcname, is a literal specifying the name of the function. Usually the literal refers to a trie with several variants. signature, is an array of literals defining the signature of the variant searched for
Examples:	/add [/doubletype /doubletype] variant pop --> /add_dd load /add [/doubletype /stringtype] variant --> false /add [/stringtype /doubletype] variant --> false /ArrayQ [/anytype] variant pop --> false /f {(hello) ==} def /f [/integertype] variant pop --> {(hello) ==}
Author:	Diesmann
FirstVersion:	090201
SeeAlso:	`Inline` `CompileMath` `def` `addtotrie` `cva`
Source:	/home/abuild/rpmbuild/BUILD/nest-2.4.1/lib/sli/typeinit.sli