public IfStatementBuilder ElseIf(Expression test, Expression body)
{
ContractUtils.RequiresNotNull(test, "test");
ContractUtils.Requires(test.Type == typeof(bool), "test");
ContractUtils.RequiresNotNull(body, "body");
_clauses.Add(Utils.IfCondition(test, body));
return(this);
}
public static Expression IfThenElse(Expression test, Expression body, Expression @else)
{
return(If(
new IfStatementTest[] {
Utils.IfCondition(test, body)
},
@else
));
}
//
// rescue stmts ... if (StandardError === $!) { stmts; }
// rescue <types> stmts ... temp1 = type1; ...; if (<temp1> === $! || ...) { stmts; }
// rescue <types> => <lvalue> stmts ... temp1 = type1; ...; if (<temp1> === $! || ...) { <lvalue> = $!; stmts; }
//
internal IfStatementTest /*!*/ Transform(AstGenerator /*!*/ gen, ResultOperation resultOperation)
{
Assert.NotNull(gen);
MSA.Expression condition;
if (_types.Length != 0)
{
var comparisonSiteStorage = Ast.Constant(new BinaryOpStorage(gen.Context));
if (_types.Length == 1)
{
condition = MakeCompareException(gen, comparisonSiteStorage, _types[0].TransformRead(gen), _types[0] is SplattedArgument);
}
else
{
// forall{i}: <temps[i]> = evaluate type[i]
var temps = new MSA.Expression[_types.Length];
var exprs = new BlockBuilder();
for (int i = 0; i < _types.Length; i++)
{
var t = _types[i].TransformRead(gen);
var tmp = gen.CurrentScope.DefineHiddenVariable("#type_" + i, t.Type);
temps[i] = tmp;
exprs.Add(Ast.Assign(tmp, t));
}
// CompareException(<temps[0]>) || ... CompareException(<temps[n]>) || CompareSplattedExceptions(<splatTypes>)
condition = MakeCompareException(gen, comparisonSiteStorage, temps[0], _types[0] is SplattedArgument);
for (int i = 1; i < _types.Length; i++)
{
condition = Ast.OrElse(condition, MakeCompareException(gen, comparisonSiteStorage, temps[i], _types[i] is SplattedArgument));
}
// (temps[0] = type[0], ..., temps[n] == type[n], condition)
exprs.Add(condition);
condition = exprs;
}
}
else
{
condition = Methods.CompareDefaultException.OpCall(gen.CurrentScopeVariable);
}
return(AstUtils.IfCondition(condition,
gen.TransformStatements(
// <lvalue> = e;
(_target != null) ? _target.TransformWrite(gen, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)) : null,
// body:
_statements,
resultOperation
)
));
}
/// <summary>
/// Transform multiple python except handlers for a try block into a single catch body.
/// </summary>
/// <param name="exception">The variable for the exception in the catch block.</param>
/// <returns>Null if there are no except handlers. Else the statement to go inside the catch handler</returns>
private MSAst.Expression TransformHandlers(MSAst.ParameterExpression exception)
{
Assert.NotEmpty(_handlers);
MSAst.ParameterExpression extracted = Ast.Variable(typeof(object), "$extracted");
var tests = new List <Microsoft.Scripting.Ast.IfStatementTest>(_handlers.Length);
MSAst.ParameterExpression converted = null;
MSAst.Expression catchAll = null;
for (int index = 0; index < _handlers.Length; index++)
{
TryStatementHandler tsh = _handlers[index];
if (tsh.Test != null)
{
Microsoft.Scripting.Ast.IfStatementTest ist;
// translating:
// except Test ...
//
// generate following AST for the Test (common part):
// CheckException(exception, Test)
MSAst.Expression test =
Ast.Call(
AstMethods.CheckException,
Parent.LocalContext,
extracted,
AstUtils.Convert(tsh.Test, typeof(object))
);
if (tsh.Target != null)
{
// translating:
// except Test, Target:
// <body>
// into:
// if ((converted = CheckException(exception, Test)) != null) {
// Target = converted;
// traceback-header
// <body>
// }
if (converted == null)
{
converted = Ast.Variable(typeof(object), "$converted");
}
ist = AstUtils.IfCondition(
Ast.NotEqual(
Ast.Assign(converted, test),
AstUtils.Constant(null)
),
Ast.Block(
tsh.Target.TransformSet(SourceSpan.None, converted, PythonOperationKind.None),
GlobalParent.AddDebugInfo(
GetTracebackHeader(
this,
exception,
tsh.Body
),
new SourceSpan(tsh.Start, tsh.Header)
),
AstUtils.Empty()
)
);
}
else
{
// translating:
// except Test:
// <body>
// into:
// if (CheckException(exception, Test) != null) {
// traceback-header
// <body>
// }
ist = AstUtils.IfCondition(
Ast.NotEqual(
test,
AstUtils.Constant(null)
),
GlobalParent.AddDebugInfo(
GetTracebackHeader(
this,
exception,
tsh.Body
),
new SourceSpan(tsh.Start, tsh.Header)
)
);
}
// Add the test to the if statement test cascade
tests.Add(ist);
}
else
{
Debug.Assert(index == _handlers.Length - 1);
Debug.Assert(catchAll == null);
// translating:
// except:
// <body>
// into:
// {
// traceback-header
// <body>
// }
catchAll = GlobalParent.AddDebugInfo(
GetTracebackHeader(this, exception, tsh.Body),
new SourceSpan(tsh.Start, tsh.Header)
);
}
}
MSAst.Expression body = null;
if (tests.Count > 0)
{
// rethrow the exception if we have no catch-all block
if (catchAll == null)
{
catchAll = Ast.Block(
Parent.GetSaveLineNumberExpression(exception, true),
Ast.Throw(
Ast.Call(
typeof(ExceptionHelpers).GetMethod("UpdateForRethrow"),
exception
)
)
);
}
body = AstUtils.If(
tests.ToArray(),
catchAll
);
}
else
{
Debug.Assert(catchAll != null);
body = catchAll;
}
IList <MSAst.ParameterExpression> args;
if (converted != null)
{
args = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression> {
converted, extracted
};
}
else
{
args = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression> {
extracted
};
}
// Codegen becomes:
// extracted = PythonOps.SetCurrentException(exception)
// < dynamic exception analysis >
return(Ast.Block(
args,
Ast.Assign(
extracted,
Ast.Call(
AstMethods.SetCurrentException,
Parent.LocalContext,
exception
)
),
body,
Ast.Assign(extracted, Ast.Constant(null)),
AstUtils.Empty()
));
}
//
// rescue stmts ... if (StandardError === $!) { stmts; }
// rescue <types> stmts ... temp1 = type1; ...; if (<temp1> === $! || ...) { stmts; }
// rescue <types> => <lvalue> stmts ... temp1 = type1; ...; if (<temp1> === $! || ...) { <lvalue> = $!; stmts; }
//
internal IfStatementTest /*!*/ Transform(AstGenerator /*!*/ gen, ResultOperation resultOperation)
{
Assert.NotNull(gen);
MSA.Expression condition;
if (_types.Count != 0 || _splatType != null)
{
if (_types.Count == 0)
{
// splat only:
condition = MakeCompareSplattedExceptions(gen, TransformSplatType(gen));
}
else if (_types.Count == 1 && _splatType == null)
{
condition = MakeCompareException(gen, _types[0].TransformRead(gen));
}
else
{
// forall{i}: <temps[i]> = evaluate type[i]
var temps = new MSA.Expression[_types.Count + (_splatType != null ? 1 : 0)];
var exprs = new MSA.Expression[temps.Length + 1];
int i = 0;
while (i < _types.Count)
{
var tmp = gen.CurrentScope.DefineHiddenVariable("#type_" + i, typeof(object));
temps[i] = tmp;
exprs[i] = Ast.Assign(tmp, _types[i].TransformRead(gen));
i++;
}
if (_splatType != null)
{
var tmp = gen.CurrentScope.DefineHiddenVariable("#type_" + i, typeof(object));
temps[i] = tmp;
exprs[i] = Ast.Assign(tmp, TransformSplatType(gen));
i++;
}
Debug.Assert(i == temps.Length);
// CompareException(<temps[0]>) || ... CompareException(<temps[n]>) || CompareSplattedExceptions(<splatTypes>)
i = 0;
condition = MakeCompareException(gen, temps[i++]);
while (i < _types.Count)
{
condition = Ast.OrElse(condition, MakeCompareException(gen, temps[i++]));
}
if (_splatType != null)
{
condition = Ast.OrElse(condition, MakeCompareSplattedExceptions(gen, temps[i++]));
}
Debug.Assert(i == temps.Length);
// (temps[0] = type[0], ..., temps[n] == type[n], condition)
exprs[exprs.Length - 1] = condition;
condition = AstFactory.Block(exprs);
}
}
else
{
condition = Methods.CompareDefaultException.OpCall(gen.CurrentScopeVariable, gen.CurrentSelfVariable);
}
return(AstUtils.IfCondition(condition,
gen.TransformStatements(
// <lvalue> = e;
(_target != null) ? _target.TransformWrite(gen, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)) : null,
// body:
_statements,
resultOperation
)
));
}
