UnionConstructor¶
A union value built from one of its members.
Declaration¶
Syntax¶
UnionConstructor(symbol dt_sym, expr* args, ttype type, expr? value)
Arguments¶
Argument |
Description |
|---|---|
|
the Union being constructed. |
|
the value of the member being set. |
|
the UnionType of the result. |
|
the compile time value of the expression, when the frontend could fold it; |
Return values¶
The value of the expression.
Description¶
Only one member of a union holds a value at a time, so a constructor takes one argument: the member being set.
Examples¶
(UnionConstructor
:dt_sym (SymbolRef 3 "word")
:args [
(IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
]
:type (UnionType
:data_member_types [
(Integer
:kind 4
)
(Real
:kind 4
)
]
)
:value nil
)
It comes from this complete ASR text document:
(TranslationUnit
:symtab (SymbolTable
:id 0
:symbols {
"m" (Module
:symtab (SymbolTable
:id 1
:symbols {
"word" (Union
:symtab (SymbolTable
:id 2
:symbols {
"i" (Variable
:parent_symtab 2
:name "i"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"r" (Variable
:parent_symtab 2
:name "r"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Real
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
}
)
:name "word"
:dependencies []
:members [
"i"
"r"
]
:abi :Source
:access :Public
:initializers []
:parent nil
)
}
)
:name "m"
:parent_module nil
:dependencies []
:loaded_from_mod false
:intrinsic false
:has_submodules false
)
"main" (Program
:symtab (SymbolTable
:id 3
:symbols {
"i" (Variable
:parent_symtab 3
:name "i"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"w" (Variable
:parent_symtab 3
:name "w"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (UnionType
:data_member_types [
(Integer
:kind 4
)
(Real
:kind 4
)
]
)
:type_declaration (SymbolRef 3 "word")
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"word" (ExternalSymbol
:parent_symtab 3
:name "word"
:external (SymbolRef 1 "word")
:module_name "m"
:scope_names []
:original_name "word"
:access :Public
)
}
)
:name "main"
:dependencies [
"m"
]
:body [
(Assignment
:target (Var
:v (SymbolRef 3 "w")
)
:value (UnionConstructor
:dt_sym (SymbolRef 3 "word")
:args [
(IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
]
:type (UnionType
:data_member_types [
(Integer
:kind 4
)
(Real
:kind 4
)
]
)
:value nil
)
:overloaded nil
:realloc_lhs false
:move_allocation false
)
(Assignment
:target (Var
:v (SymbolRef 3 "i")
)
:value (UnionInstanceMember
:v (Var
:v (SymbolRef 3 "w")
)
:m (SymbolRef 2 "i")
:type (Integer
:kind 4
)
:value nil
)
:overloaded nil
:realloc_lhs false
:move_allocation false
)
]
)
}
)
:items []
)