Block¶
The Block is a symbol node that represents a scoped list of statements
(block).
Declaration¶
Syntax¶
Block(symbol_table symtab, identifier name, stmt* body)
Arguments¶
Argument Name |
Denotes |
|---|---|
|
the parent symbol table that contains the block |
|
the name of the block in the parent symbol table |
|
the list of statements in the block |
Return values¶
None.
Description¶
The Block node represents a scoped list of statements. In C one uses {} to
represent a block, in Fortran one uses block / end block. The Block
contains its own symbol table and can contain variable declarations that are
local to the block.
The Block itself is part of a symbol table and one uses the BlockCall stmt
node to call (enter) the block from a list of statements.
A BlockCall is different from a FunctionCall in the sense that it does
not expect/accept any arguments. Also,
the statements inside a Block can access the variables in the parent/caller
scope, unlike Function where statements cannot access variables of the caller
scope.
Types¶
Examples¶
An example in C is:
{
int i = 5;
print("%d\n", i);
}
An example in Fortran is:
program test_block
integer :: i
i = 5
block
integer :: j
j = i + 1
print *, i, j
end block
end program
ASR:
(TranslationUnit
(SymbolTable
1
{
test_block:
(Program
(SymbolTable
2
{
block:
(Block
(SymbolTable
3
{
j:
(Variable
3
j
[]
Local
()
()
Default
(Integer 4 [])
Source
Public
Required
.false.
)
})
block
[(=
(Var 3 j)
(IntegerBinOp
(Var 2 i)
Add
(IntegerConstant 1 (Integer 4 []))
(Integer 4 [])
()
)
()
)
(Print
()
[(Var 2 i)
(Var 3 j)]
()
()
)]
),
i:
(Variable
2
i
[]
Local
()
()
Default
(Integer 4 [])
Source
Public
Required
.false.
)
})
test_block
[]
[(=
(Var 2 i)
(IntegerConstant 5 (Integer 4 []))
()
)
(BlockCall
-1
2 block
)]
)
})
[]
)