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ceriel
1988-10-26 15:21:11 +00:00
parent a7a80689bf
commit 01252cb592
60 changed files with 11297 additions and 0 deletions
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lang/pc/comp/statement.g Normal file
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/* S T A T E M E N T S */
{
#include <alloc.h>
#include <em.h>
#include "LLlex.h"
#include "chk_expr.h"
#include "def.h"
#include "desig.h"
#include "idf.h"
#include "main.h"
#include "node.h"
#include "scope.h"
#include "type.h"
int slevel = 0; /* nesting level of statements */
}
/* ISO section 6.8.3.2, p. 128 */
CompoundStatement:
BEGIN StatementSequence END
;
/* ISO section 6.8.3.1, p. 128 */
StatementSequence:
Statement
[ %persistent
';' Statement
]*
{ chk_labels(slevel + 1); }
;
/* ISO section 6.8.1, p. 126 */
Statement
{
struct node *nd;
} :
{
slevel++;
}
[ Label(&nd) ':'
{ if( nd ) DefLabel(nd, slevel); }
]?
{ if( !options['L'] )
C_lin((arith) dot.tk_lineno);
}
[
SimpleStatement
|
StructuredStatement
]
{ slevel--; }
;
/* ISO section 6.8.2.1, p. 126 */
SimpleStatement
{
struct node *pnd, *expp;
} :
/* This is a changed rule, because the grammar as specified in the
* reference is not LL(1), and this gives conflicts.
* Note : the grammar states : AssignmentStatement |
* ProcedureStatement | ...
*/
EmptyStatement
|
GotoStatement
|
/* Evidently this is the beginning of the changed part
*/
IDENT { pnd = MkLeaf(Name, &dot); }
[
/* At this point the IDENT can be a FunctionIdentifier in
* which case the VariableAccessTail must be empty.
*/
VariableAccessTail(&pnd)
[
BECOMES
|
'=' { error("':=' expected instead of '='"); }
]
Expression(&expp)
{ AssignStat(pnd, expp); }
|
{ pnd = MkNode(Call, pnd, NULLNODE, &dot); }
ActualParameterList(&(pnd->nd_right))?
{ ProcStat(pnd);
if( !err_occurred )
CodeCall(pnd);
FreeNode(pnd);
}
]
|
InputOutputStatement
/* end of changed part
*/
;
InputOutputStatement
{
struct node *nd = NULLNODE;
} :
/* This is a new rule because the grammar specified by the standard
* is not exactly LL(1) (see SimpleStatement).
*/
[
READ ReadParameterList(&nd) { ChkRead(nd); }
|
READLN ReadParameterList(&nd)? { ChkReadln(nd); }
|
WRITE WriteParameterList(&nd) { ChkWrite(nd); }
|
WRITELN WriteParameterList(&nd)? { ChkWriteln(nd); }
]
{ FreeNode(nd); }
;
EmptyStatement:
/* empty */
;
/* ISO section 6.8.3.1, p. 128 */
StructuredStatement:
CompoundStatement
|
ConditionalStatement
|
RepetitiveStatement
|
WithStatement
;
/* ISO section 6.8.2.4, p. 127 */
GotoStatement
{
struct node *nd;
} :
GOTO Label(&nd)
{ if( nd ) TstLabel(nd, slevel); }
;
/* ISO section 6.8.3.3, p. 128 */
ConditionalStatement:
%default
CaseStatement
|
IfStatement
;
/* ISO section 6.8.3.6, p. 129 */
RepetitiveStatement:
RepeatStatement
|
WhileStatement
|
ForStatement
;
/* ISO section 6.8.3.10, p. 132 */
WithStatement
{
struct scopelist *Save = CurrVis;
struct node *nd;
} :
WITH
RecordVariableList(&nd)
DO
Statement { EndWith(Save, nd);
chk_labels(slevel + 1);
}
;
RecordVariableList(register struct node **pnd;)
{
struct node *nd;
} :
RecordVariable(&nd)
{ *pnd = nd = MkNode(Link, nd, NULLNODE, &dot);
nd->nd_symb = ',';
}
[ %persistent
',' { nd->nd_right = MkLeaf(Link, &dot);
nd = nd->nd_right;
}
RecordVariable(&(nd->nd_left))
]*
;
RecordVariable(register struct node **pnd;):
VariableAccess(pnd)
{ WithStat(*pnd); }
;
/* ISO section 6.8.3.4, p. 128 */
IfStatement
{
struct node *nd;
label l1 = ++text_label;
label l2 = ++text_label;
} :
IF
BooleanExpression(&nd)
{ struct desig ds;
ds = InitDesig;
if( !err_occurred )
CodeExpr(nd, &ds, l1);
}
THEN
Statement { chk_labels(slevel + 1); }
[ %prefer /* closest matching */
ELSE
{ C_bra(l2);
C_df_ilb(l1);
}
Statement
{ C_df_ilb(l2);
chk_labels(slevel + 1);
}
|
/* empty */
{ C_df_ilb(l1); }
]
;
/* ISO section 6.8.3.5, p. 128 */
CaseStatement
{
struct node *casend, *nd;
label exit_label;
} :
/* This is a changed rule, because the grammar as specified in the
* reference states that a semicolon is optional before END,
* and this is not LL(1).
*/
CASE { casend = nd = MkLeaf(Link, &dot);
casend->nd_lab = ++text_label;
exit_label = ++text_label;
}
Expression(&(nd->nd_left))
{ CaseExpr(casend); }
OF
CaseListElement(&(nd->nd_right), exit_label)
{ nd = nd->nd_right; }
CaseListElementTail(&(nd->nd_right), exit_label)
END
{ CaseEnd(casend, exit_label); }
;
CaseListElementTail(register struct node **pnd; label exit_label;):
/* This is a new rule, all because of a silly semicolon
*/
/* empty */
|
%default
';'
[
/* empty */
|
CaseListElement(pnd, exit_label)
CaseListElementTail(&((*pnd)->nd_right), exit_label)
]
;
CaseListElement(register struct node **pnd; label exit_label;):
CaseConstantList(pnd)
':'
{ *pnd = MkNode(Link, *pnd, NULLNODE, &dot);
(*pnd)->nd_lab = ++text_label;
C_df_ilb(text_label);
}
Statement { C_bra(exit_label);
chk_labels(slevel + 1);
}
;
/* ISO section 6.8.3.7, p. 129 */
RepeatStatement
{
struct node *nd;
label repeatlb = ++text_label;
} :
REPEAT
{ C_df_ilb(repeatlb); }
StatementSequence
UNTIL
BooleanExpression(&nd)
{ struct desig ds;
ds = InitDesig;
if( !err_occurred )
CodeExpr(nd, &ds, repeatlb);
}
;
/* ISO section 6.8.3.8, p. 129 */
WhileStatement
{
struct node *nd;
label whilelb = ++text_label;
label exitlb = ++text_label;
} :
WHILE
{ C_df_ilb(whilelb); }
BooleanExpression(&nd)
{ struct desig ds;
ds = InitDesig;
if( !err_occurred )
CodeExpr(nd, &ds, exitlb);
}
DO
Statement
{ C_bra(whilelb);
C_df_ilb(exitlb);
chk_labels(slevel + 1);
}
;
/* ISO section 6.8.3.9, p. 130 */
ForStatement
{
register struct node *nd;
int stepsize;
label l1 = ++text_label;
label l2 = ++text_label;
arith tmp1 = (arith) 0;
arith tmp2 = (arith) 0;
} :
FOR
/* ControlVariable must be an EntireVariable */
IDENT { nd = MkLeaf(Name, &dot); }
BECOMES
Expression(&(nd->nd_left))
[
TO { stepsize = 1; }
|
DOWNTO { stepsize = -1; }
]
Expression(&(nd->nd_right))
{ ChkForStat(nd);
if( !err_occurred ) {
tmp1 = CodeInitFor(nd->nd_left, 0);
tmp2 = CodeInitFor(nd->nd_right, 2);
CodeFor(nd, stepsize, l1, l2, tmp1);
}
}
DO
Statement
{ if( !err_occurred )
CodeEndFor(nd, stepsize, l1, l2, tmp2);
chk_labels(slevel + 1);
FreeNode(nd);
if( tmp1 ) FreeInt(tmp1);
if( tmp2 ) FreeInt(tmp2);
}
;
/* SPECIALSPECIALSPECIALSPECIALSPECIALSPECIALSPECIALSPECIALSPECIALSPECIAL */
/* ISO section 6.9, p. 132-136 */
ReadParameterList(register struct node **pnd;)
{
register struct node *nd;
} :
/* This is a changed rule, because the grammar as specified in the
* reference is not LL(1), and this gives conflicts.
*/
'('
VariableAccess(pnd) /* possibly a FileVariable */
{ *pnd = nd =
MkNode(Link, *pnd, NULLNODE, &dot);
nd->nd_symb = ',';
}
[ %persistent
',' { nd->nd_right = MkLeaf(Link, &dot);
nd = nd->nd_right;
}
VariableAccess(&(nd->nd_left))
]*
')'
;
WriteParameterList(register struct node **pnd;)
{
register struct node *nd;
} :
/* This is a changed rule, because the grammar as specified in the
* reference is not LL(1), and this gives conflicts.
*/
'('
/* Only the first WriteParameter can be a FileVariable !!
*/
WriteParameter(pnd)
{ *pnd = nd =
MkNode(Link, *pnd, NULLNODE, &dot);
nd->nd_symb = ',';
}
[ %persistent
',' { nd->nd_right = MkLeaf(Link, &dot);
nd = nd->nd_right;
}
WriteParameter(&(nd->nd_left))
]*
')'
;
WriteParameter(register struct node **pnd;)
{
register struct node *nd;
} :
Expression(pnd)
{ if( !ChkExpression(*pnd) )
(*pnd)->nd_type = error_type;
*pnd = nd =
MkNode(Link, *pnd, NULLNODE, &dot);
nd->nd_symb = ':';
}
[
/* Here the first Expression can't be a FileVariable
*/
':' { nd->nd_right = MkLeaf(Link, &dot);
nd = nd->nd_right;
}
Expression(&(nd->nd_left))
{ if( !ChkExpression(nd->nd_left) )
nd->nd_left->nd_type = error_type;
}
[
':' { nd->nd_right = MkLeaf(Link, &dot);
nd = nd->nd_right;
}
Expression(&(nd->nd_left))
{ if( !ChkExpression(nd->nd_left) )
nd->nd_left->nd_type = error_type;
}
]?
]?
;