// generateNominalUnwrapping generates the expression source for the unwrapping of a nominal instance of a base type.
func (eg *expressionGenerator) generateNominalUnwrapping(nominalUnwrapping *codedom.NominalUnwrappingNode, context generationContext) esbuilder.ExpressionBuilder {
// If this is an unwrap is of a wrap, then try to either cancel both operations (if we can),
// or simplify the unwrapping operation.
childExpression := nominalUnwrapping.ChildExpression
if wrapping, ok := nominalUnwrapping.ChildExpression.(*codedom.NominalWrappingNode); ok {
// If the value that was being wrapped is, itself, nominal or structural, then we still
// need to unwrap it, but we can fast-path by ignoring the wrap and directly unwrapping
// the nominal/struct. Otherwise, we can simply just collapse the unwrap+wrap into a NOOP.
if !wrapping.IsLiteralWrap && wrapping.ChildExpressionType.IsNominalOrStruct() {
childExpression = wrapping.ChildExpression
} else {
// Otherwise, we can just collapse both operations into nothing.
return eg.generateExpression(wrapping.ChildExpression, context)
}
}
// If the child expression being unwrapped is non-nullable and we know it is boxed, then
// we can use a fast-path unbox call without the extra checks.
if !nominalUnwrapping.ChildExpressionType.NullValueAllowed() &&
nominalUnwrapping.ChildExpressionType.IsNominalOrStruct() {
access := codedom.NativeAccess(
childExpression,
codedom.BoxedDataProperty,
nominalUnwrapping.BasisNode())
return eg.generateExpression(access, context)
}
call := codedom.RuntimeFunctionCall(
codedom.UnboxFunction,
[]codedom.Expression{
childExpression,
},
nominalUnwrapping.BasisNode())
return eg.generateExpression(call, context)
}
// generateMemberAssignment generates the expression source for a member assignment.
func (eg *expressionGenerator) generateMemberAssignment(memberAssign *codedom.MemberAssignmentNode, context generationContext) esbuilder.ExpressionBuilder {
basisNode := memberAssign.BasisNode()
// If the target member is an operator, then we need to invoke it as a function call, with the first
// argument being the argument to the child call, and the second argument being the assigned child
// expression.
if memberAssign.Target.IsOperator() {
childCall := memberAssign.NameExpression.(*codedom.MemberCallNode)
memberRef := childCall.ChildExpression.(*codedom.MemberReferenceNode)
// If this is a native operator, change it into a native indexing and assignment.
if memberAssign.Target.IsNative() {
nativeAssign := codedom.NativeAssign(
codedom.NativeIndexing(memberRef.ChildExpression,
childCall.Arguments[0], basisNode),
memberAssign.Value,
basisNode)
return eg.generateExpression(nativeAssign, context)
} else {
memberCall := codedom.MemberCall(
codedom.NativeAccess(memberRef.ChildExpression, eg.pather.GetMemberName(memberAssign.Target), memberRef.BasisNode()),
memberAssign.Target,
[]codedom.Expression{childCall.Arguments[0], memberAssign.Value},
basisNode)
return eg.generateExpression(memberCall, context)
}
}
// If the target member is implicitly called, then this is a property that needs to be assigned via a call.
if memberAssign.Target.IsImplicitlyCalled() {
memberRef := memberAssign.NameExpression.(*codedom.MemberReferenceNode)
memberCall := codedom.MemberCall(
codedom.NativeAccess(memberRef.ChildExpression, eg.pather.GetSetterName(memberRef.Member), memberRef.BasisNode()),
memberAssign.Target,
[]codedom.Expression{memberAssign.Value},
basisNode)
return eg.generateExpression(memberCall, context)
}
value := eg.generateExpression(memberAssign.Value, context)
targetExpr := eg.generateExpression(memberAssign.NameExpression, context)
return esbuilder.Assignment(targetExpr, value)
}
// generateMemberReference generates the expression for a reference to a module or type member.
func (eg *expressionGenerator) generateMemberReference(memberReference *codedom.MemberReferenceNode, context generationContext) esbuilder.ExpressionBuilder {
// If the target member is implicitly called, then this is a property that needs to be accessed via a call.
if memberReference.Member.IsImplicitlyCalled() {
basisNode := memberReference.BasisNode()
memberCall := codedom.MemberCall(
codedom.NativeAccess(memberReference.ChildExpression, memberReference.Member.Name(), basisNode),
memberReference.Member,
[]codedom.Expression{},
basisNode)
return eg.generateExpression(memberCall, context)
}
// This handles the native new case for WebIDL. We should probably handle this directly.
if memberReference.Member.IsStatic() && !memberReference.Member.IsPromising() {
return eg.generateExpression(codedom.StaticMemberReference(memberReference.Member, eg.scopegraph.TypeGraph().AnyTypeReference(), memberReference.BasisNode()), context)
}
childExpr := eg.generateExpression(memberReference.ChildExpression, context)
return childExpr.Member(eg.pather.GetMemberName(memberReference.Member))
}
// buildLoopStatement builds the CodeDOM for a loop statement.
func (db *domBuilder) buildLoopStatement(node compilergraph.GraphNode) (codedom.Statement, codedom.Statement) {
startStatement := codedom.EmptyStatement(node)
startStatement.MarkReferenceable()
finalStatement := codedom.EmptyStatement(node)
// Save initial continue and break statements for the loop.
db.continueStatementMap[node.NodeId] = startStatement
db.breakStatementMap[node.NodeId] = finalStatement
// A loop statement is buildd as a start statement which conditionally jumps to either the loop body
// (on true) or, on false, jumps to a final state after the loop.
if loopExpr, hasLoopExpr := db.tryGetExpression(node, parser.NodeLoopStatementExpression); hasLoopExpr {
// Check for a named value under the loop. If found, this is a loop over a stream or streamable.
namedValue, hasNamedValue := node.TryGetNode(parser.NodeStatementNamedValue)
if hasNamedValue {
namedValueName := namedValue.Get(parser.NodeNamedValueName)
resultVarName := db.generateScopeVarName(node)
namedValueScope, _ := db.scopegraph.GetScope(namedValue)
// Create the stream variable.
streamVarName := db.generateScopeVarName(node)
var streamVariable = codedom.VarDefinitionWithInit(streamVarName, loopExpr, node)
// If the expression is Streamable, first call .Stream() on the expression to get the stream
// for the variable.
if namedValueScope.HasLabel(proto.ScopeLabel_STREAMABLE_LOOP) {
// Call .Stream() on the expression.
streamableMember, _ := db.scopegraph.TypeGraph().StreamableType().GetMember("Stream")
streamExpr := codedom.MemberCall(
codedom.MemberReference(loopExpr, streamableMember, namedValue),
streamableMember,
[]codedom.Expression{},
namedValue)
streamVariable = codedom.VarDefinitionWithInit(streamVarName, streamExpr, node)
}
// Create variables to hold the named value (as requested in the SRG) and the loop result.
namedVariable := codedom.VarDefinition(namedValueName, node)
resultVariable := codedom.VarDefinition(resultVarName, node)
// Create an expression statement to set the result variable to a call to Next().
streamMember, _ := db.scopegraph.TypeGraph().StreamType().GetMember("Next")
nextCallExpr := codedom.MemberCall(
codedom.MemberReference(codedom.LocalReference(streamVarName, node), streamMember, node),
streamMember,
[]codedom.Expression{},
namedValue)
resultExpressionStatement := codedom.ExpressionStatement(codedom.LocalAssignment(resultVarName, nextCallExpr, namedValue), namedValue)
resultExpressionStatement.MarkReferenceable()
// Set the continue statement to call Next() again.
db.continueStatementMap[node.NodeId] = resultExpressionStatement
// Create an expression statement to set the named variable to the first part of the tuple.
namedExpressionStatement := codedom.ExpressionStatement(
codedom.LocalAssignment(namedValueName,
codedom.NativeAccess(
codedom.LocalReference(resultVarName, namedValue), "First", namedValue),
namedValue),
namedValue)
// Jump to the body state if the second part of the tuple in the result variable is true.
bodyStart, bodyEnd := db.getStatements(node, parser.NodeLoopStatementBlock)
checkJump := codedom.ConditionalJump(
codedom.NativeAccess(codedom.LocalReference(resultVarName, node), "Second", node),
bodyStart,
finalStatement,
node)
// Steps:
// 1) Empty statement
// 2) Create the stream's variable (with no value)
// 3) Create the named value variable (with no value)
// 4) Create the result variable (with no value)
// 5) (loop starts here) Pull the Next() result out of the stream
// 6) Pull the true/false bool out of the result
// 7) Pull the named value out of the result
// 8) Jump based on the true/false boolean value
codedom.AssignNextStatement(startStatement, streamVariable)
codedom.AssignNextStatement(streamVariable, namedVariable)
codedom.AssignNextStatement(namedVariable, resultVariable)
codedom.AssignNextStatement(resultVariable, resultExpressionStatement)
codedom.AssignNextStatement(resultExpressionStatement, namedExpressionStatement)
codedom.AssignNextStatement(namedExpressionStatement, checkJump)
// Jump to the result checking expression once the loop body completes.
directJump := codedom.UnconditionalJump(resultExpressionStatement, node)
codedom.AssignNextStatement(bodyEnd, directJump)
return startStatement, finalStatement
} else {
bodyStart, bodyEnd := db.getStatements(node, parser.NodeLoopStatementBlock)
// Loop over a direct boolean expression which is evaluated on each iteration.
initialJump := codedom.ConditionalJump(loopExpr, bodyStart, finalStatement, node)
directJump := codedom.UnconditionalJump(initialJump, node)
codedom.AssignNextStatement(bodyEnd, directJump)
codedom.AssignNextStatement(startStatement, initialJump)
return startStatement, finalStatement
}
} else {
bodyStart, bodyEnd := db.getStatements(node, parser.NodeLoopStatementBlock)
// A loop without an expression just loops infinitely over the body.
directJump := codedom.UnconditionalJump(bodyStart, node)
codedom.AssignNextStatement(bodyEnd, directJump)
codedom.AssignNextStatement(startStatement, bodyStart)
return startStatement, directJump
}
}