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Module dmd.dtemplate

Defines TemplateDeclaration, TemplateInstance and a few utilities

This modules holds the two main template types: TemplateDeclaration, which is the user-provided declaration of a template, and TemplateInstance, which is an instance of a TemplateDeclaration with specific arguments.

Template Parameter

Additionally, the classes for template parameters are defined in this module. The base class, TemplateParameter, is inherited by: - TemplateTypeParameter - TemplateThisParameter - TemplateValueParameter - TemplateAliasParameter - TemplateTupleParameter

Templates semantic

The start of the template instantiation process looks like this: - A TypeInstance or TypeIdentifier is encountered. TypeInstance have a bang (e.g. Foo!(arg)) while TypeIdentifier don't. - A TemplateInstance is instantiated - Semantic is run on the TemplateInstance (see dmd.dsymbolsem) - The TemplateInstance search for its TemplateDeclaration, runs semantic on the template arguments and deduce the best match among the possible overloads. - The TemplateInstance search for existing instances with the same arguments, and uses it if found. - Otherwise, the rest of semantic is run on the TemplateInstance.

Documentation

https://dlang.org/phobos/dmd_dtemplate.html

Coverage

https://codecov.io/gh/dlang/dmd/src/master/src/dmd/dtemplate.d

Functions

NameDescription
arrayObjectIsError(args) Are any of the Objects an error?
arrayObjectMatch(oa1, oa2) Match an array of them.
definitelyValueParameter(e) Return true if e could be valid only as a template value parameter. Return false if it might be an alias or tuple. (Note that even in this case, it could still turn out to be a value).
getDsymbol(oarg) If oarg represents a Dsymbol, return that Dsymbol
getType(o) Try to get arg as a type.
isError(o) Is this Object an error?
isExpression(o) These functions substitute for dynamic_cast. dynamic_cast does not work on earlier versions of gcc.
matchArg(tp, instLoc, sc, tiargs, i, parameters, dedtypes, psparam) Match to a particular TemplateParameter.
printTemplateStats(listInstances, eSink) Print informational statistics on template instantiations.
reliesOnTemplateParameters(t, tparams) Check whether the type t representation relies on one or more the template parameters.
reliesOnTident(t, tparams, iStart) Check whether the type t representation relies on one or more the template parameters.
unSpeculative(sc, o) IsExpression can evaluate the specified type speculatively, and even if it instantiates any symbols, they are normally unnecessary for the final executable. However, if those symbols leak to the actual code, compiler should remark them as non-speculative to generate their code and link to the final executable.

Classes

NameDescription
TemplateAliasParameter
TemplateDeclaration [mixin] template Identifier (parameters) [Constraint]
TemplateInstance
TemplateMixin
TemplateParameter
TemplateThisParameter
TemplateTupleParameter
TemplateTypeParameter
TemplateValueParameter

Structs

NameDescription
MATCHpair Pair of MATCHes
TemplateInstanceBox This struct is needed for TemplateInstance to be the key in an associative array. Fixing https://issues.dlang.org/show_bug.cgi?id=15813 would make it unnecessary.
TemplateStats Collect and print statistics on template instantiations.

Authors

Walter Bright

License

Boost License 1.0