Assignment¶
Assignment statement, a statement (stmt) node.
Declaration¶
Syntax¶
Assignment(expr target, expr value, stmt? overloaded, bool realloc_lhs, bool move_allocation)
Arguments¶
target contains expression target.
value expressions giving the value to be assigned.
overloaded denotes if overloaded.
realloc_lhs denotes if target has to be reallocated to the size of value before the assignment.
move_allocation denotes if this is a move assignment for allocatable arrays.
Return values¶
None.
Description¶
assignment statement assigns a value to a variable, substring, array element, record, or record field.
The value can be a constant or the result of an expression. The kinds of assignment statements: are arithmetic, logical, character, and record assignments.
If realloc_lhs is true then before the assignment the target is reallocated to the size of the value.
move_allocation must only be true if both target and value are allocatable arrays of DescriptorArray physical type. The data pointer of value’s descriptor is copied to the target’s descriptor. And rest of the fields of value’s descriptor are copied into target’s descriptor. After the move, the data pointer of value’s descriptor is set to null.
Types¶
Numeric type, a name of a variable, array element, or record field. Arithmentic expression, chracter constant, or a logical expression.
Examples¶
module overload_assignment_m
implicit none
private
public assignment (=)
interface assignment (=)
module procedure logical_gets_integer
end interface
contains
subroutine logical_gets_integer(tf, i)
logical, intent (out) :: tf
integer, intent (in) :: i
tf = (i == 0)
end subroutine
subroutine logical_gets_integer_use(tf, i)
logical, intent (out) :: tf
integer, intent (in) :: i
tf = i
end subroutine
end module
program main
use overload_assignment_m, only: assignment(=)
implicit none
logical :: tf
tf = 0
print *, "tf=0:", tf ! Yields: T
tf = 1
print *, "tf=1:", tf ! Yields: F
end program
ASR:
(TranslationUnit
(SymbolTable
1
{
main:
(Program
(SymbolTable
5
{
logical_gets_integer@~assign:
(ExternalSymbol
5
logical_gets_integer@~assign
2 logical_gets_integer
overload_assignment_m
[]
logical_gets_integer
Private
),
tf:
(Variable
5
tf
Local
()
()
Default
(Logical 4 [])
Source
Private
Required
.false.
),
~assign:
(ExternalSymbol
5
~assign
2 ~assign
overload_assignment_m
[]
~assign
Private
)
})
main
[overload_assignment_m]
[(=
(Var 5 tf)
(IntegerConstant 0 (Integer 4 []))
(SubroutineCall
5 logical_gets_integer@~assign
5 ~assign
[((Var 5 tf))
((IntegerConstant 0 (Integer 4 [])))]
()
)
)
(Print
()
[(StringConstant
"tf=0:"
(Character 1 5 () [])
)
(Var 5 tf)]
()
()
)
(=
(Var 5 tf)
(IntegerConstant 1 (Integer 4 []))
(SubroutineCall
5 logical_gets_integer@~assign
5 ~assign
[((Var 5 tf))
((IntegerConstant 1 (Integer 4 [])))]
()
)
)
(Print
()
[(StringConstant
"tf=1:"
(Character 1 5 () [])
)
(Var 5 tf)]
()
()
)]
),
overload_assignment_m:
(Module
(SymbolTable
2
{
logical_gets_integer:
(Function
(SymbolTable
3
{
i:
(Variable
3
i
In
()
()
Default
(Integer 4 [])
Source
Private
Required
.false.
),
tf:
(Variable
3
tf
Out
()
()
Default
(Logical 4 [])
Source
Private
Required
.false.
)
})
logical_gets_integer
[(Var 3 tf)
(Var 3 i)]
[(=
(Var 3 tf)
(IntegerCompare
(Var 3 i)
Eq
(IntegerConstant 0 (Integer 4 []))
(Logical 4 [])
()
)
()
)]
()
Source
Private
Implementation
()
.false.
.false.
.false.
.false.
.false.
[]
[]
.false.
),
logical_gets_integer_use:
(Function
(SymbolTable
4
{
i:
(Variable
4
i
In
()
()
Default
(Integer 4 [])
Source
Private
Required
.false.
),
tf:
(Variable
4
tf
Out
()
()
Default
(Logical 4 [])
Source
Private
Required
.false.
)
})
logical_gets_integer_use
[(Var 4 tf)
(Var 4 i)]
[(=
(Var 4 tf)
(Var 4 i)
(SubroutineCall
2 logical_gets_integer
2 ~assign
[((Var 4 tf))
((Var 4 i))]
()
)
)]
()
Source
Private
Implementation
()
.false.
.false.
.false.
.false.
.false.
[]
[]
.false.
),
~assign:
(CustomOperator
2
~assign
[2 logical_gets_integer]
Public
)
})
overload_assignment_m
[]
.false.
.false.
)
})
[]
)