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Code Issues Packages Projects Releases 10 Wiki Activity

Switch Statement to use inheritance+cast (#718)

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This commit is contained in:
Jon Meow
2021-08-10 13:10:05 -07:00
committed by GitHub
parent 9168375978
commit d5564280ab
5 changed files with 535 additions and 567 deletions
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executable_semantics/interpreter/interpreter.cpp
+62 -59
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@@ -805,8 +805,8 @@ void StepPattern() {
auto IsWhileAct(Action* act) -> bool {
switch (act->Tag()) {
case Action::Kind::StatementAction:
switch (cast<StatementAction>(*act).Stmt()->tag()) {
case StatementKind::While:
switch (cast<StatementAction>(*act).Stmt()->Tag()) {
case Statement::Kind::While:
return true;
default:
return false;
@@ -819,8 +819,8 @@ auto IsWhileAct(Action* act) -> bool {
auto IsBlockAct(Action* act) -> bool {
switch (act->Tag()) {
case Action::Kind::StatementAction:
switch (cast<StatementAction>(*act).Stmt()->tag()) {
case StatementKind::Block:
switch (cast<StatementAction>(*act).Stmt()->Tag()) {
case Statement::Kind::Block:
return true;
default:
return false;
@@ -842,13 +842,13 @@ void StepStmt() {
stmt->PrintDepth(1, llvm::outs());
llvm::outs() << " --->\n";
}
switch (stmt->tag()) {
case StatementKind::Match:
switch (stmt->Tag()) {
case Statement::Kind::Match:
if (act->Pos() == 0) {
// { { (match (e) ...) :: C, E, F} :: S, H}
// -> { { e :: (match ([]) ...) :: C, E, F} :: S, H}
frame->todo.Push(
global_arena->New<ExpressionAction>(stmt->GetMatch().exp));
global_arena->New<ExpressionAction>(cast<Match>(*stmt).Exp()));
act->IncrementPos();
} else {
// Regarding act->Pos():
@@ -861,11 +861,12 @@ void StepStmt() {
// * 2: the pattern for clause 1
// * ...
auto clause_num = (act->Pos() - 1) / 2;
if (clause_num >= static_cast<int>(stmt->GetMatch().clauses->size())) {
if (clause_num >=
static_cast<int>(cast<Match>(*stmt).Clauses()->size())) {
frame->todo.Pop(1);
break;
}
auto c = stmt->GetMatch().clauses->begin();
auto c = cast<Match>(*stmt).Clauses()->begin();
std::advance(c, clause_num);
if (act->Pos() % 2 == 1) {
@@ -880,12 +881,12 @@ void StepStmt() {
auto values = CurrentEnv(state);
std::list<std::string> vars;
std::optional<Env> matches =
PatternMatch(pat, v, values, &vars, stmt->line_num);
PatternMatch(pat, v, values, &vars, stmt->LineNumber());
if (matches) { // we have a match, start the body
auto* new_scope = global_arena->New<Scope>(*matches, vars);
frame->scopes.Push(new_scope);
const Statement* body_block =
Statement::MakeBlock(stmt->line_num, c->second);
global_arena->New<Block>(stmt->LineNumber(), c->second);
Action* body_act = global_arena->New<StatementAction>(body_block);
body_act->IncrementPos();
frame->todo.Pop(1);
@@ -896,26 +897,26 @@ void StepStmt() {
act->IncrementPos();
clause_num = (act->Pos() - 1) / 2;
if (clause_num ==
static_cast<int>(stmt->GetMatch().clauses->size())) {
static_cast<int>(cast<Match>(*stmt).Clauses()->size())) {
frame->todo.Pop(1);
}
}
}
}
break;
case StatementKind::While:
case Statement::Kind::While:
if (act->Pos() == 0) {
// { { (while (e) s) :: C, E, F} :: S, H}
// -> { { e :: (while ([]) s) :: C, E, F} :: S, H}
frame->todo.Push(
global_arena->New<ExpressionAction>(stmt->GetWhile().cond));
global_arena->New<ExpressionAction>(cast<While>(*stmt).Cond()));
act->IncrementPos();
} else if (cast<BoolValue>(*act->Results()[0]).Val()) {
// { {true :: (while ([]) s) :: C, E, F} :: S, H}
// -> { { s :: (while (e) s) :: C, E, F } :: S, H}
frame->todo.Top()->Clear();
frame->todo.Push(
global_arena->New<StatementAction>(stmt->GetWhile().body));
global_arena->New<StatementAction>(cast<While>(*stmt).Body()));
} else {
// { {false :: (while ([]) s) :: C, E, F} :: S, H}
// -> { { C, E, F } :: S, H}
@@ -923,41 +924,41 @@ void StepStmt() {
frame->todo.Pop(1);
}
break;
case StatementKind::Break:
case Statement::Kind::Break:
CHECK(act->Pos() == 0);
// { { break; :: ... :: (while (e) s) :: C, E, F} :: S, H}
// -> { { C, E', F} :: S, H}
frame->todo.Pop(1);
while (!frame->todo.IsEmpty() && !IsWhileAct(frame->todo.Top())) {
if (IsBlockAct(frame->todo.Top())) {
DeallocateScope(stmt->line_num, frame->scopes.Top());
DeallocateScope(stmt->LineNumber(), frame->scopes.Top());
frame->scopes.Pop(1);
}
frame->todo.Pop(1);
}
frame->todo.Pop(1);
break;
case StatementKind::Continue:
case Statement::Kind::Continue:
CHECK(act->Pos() == 0);
// { { continue; :: ... :: (while (e) s) :: C, E, F} :: S, H}
// -> { { (while (e) s) :: C, E', F} :: S, H}
frame->todo.Pop(1);
while (!frame->todo.IsEmpty() && !IsWhileAct(frame->todo.Top())) {
if (IsBlockAct(frame->todo.Top())) {
DeallocateScope(stmt->line_num, frame->scopes.Top());
DeallocateScope(stmt->LineNumber(), frame->scopes.Top());
frame->scopes.Pop(1);
}
frame->todo.Pop(1);
}
break;
case StatementKind::Block: {
case Statement::Kind::Block: {
if (act->Pos() == 0) {
if (stmt->GetBlock().stmt) {
if (cast<Block>(*stmt).Stmt()) {
auto* scope = global_arena->New<Scope>(CurrentEnv(state),
std::list<std::string>());
frame->scopes.Push(scope);
frame->todo.Push(
global_arena->New<StatementAction>(stmt->GetBlock().stmt));
global_arena->New<StatementAction>(cast<Block>(*stmt).Stmt()));
act->IncrementPos();
act->IncrementPos();
} else {
@@ -965,22 +966,22 @@ void StepStmt() {
}
} else {
Scope* scope = frame->scopes.Top();
DeallocateScope(stmt->line_num, scope);
DeallocateScope(stmt->LineNumber(), scope);
frame->scopes.Pop(1);
frame->todo.Pop(1);
}
break;
}
case StatementKind::VariableDefinition:
case Statement::Kind::VariableDefinition:
if (act->Pos() == 0) {
// { {(var x = e) :: C, E, F} :: S, H}
// -> { {e :: (var x = []) :: C, E, F} :: S, H}
frame->todo.Push(global_arena->New<ExpressionAction>(
stmt->GetVariableDefinition().init));
cast<VariableDefinition>(*stmt).Init()));
act->IncrementPos();
} else if (act->Pos() == 1) {
frame->todo.Push(global_arena->New<PatternAction>(
stmt->GetVariableDefinition().pat));
cast<VariableDefinition>(*stmt).Pat()));
act->IncrementPos();
} else if (act->Pos() == 2) {
// { { v :: (x = []) :: C, E, F} :: S, H}
@@ -990,52 +991,53 @@ void StepStmt() {
std::optional<Env> matches =
PatternMatch(p, v, frame->scopes.Top()->values,
&frame->scopes.Top()->locals, stmt->line_num);
&frame->scopes.Top()->locals, stmt->LineNumber());
CHECK(matches)
<< stmt->line_num
<< stmt->LineNumber()
<< ": internal error in variable definition, match failed";
frame->scopes.Top()->values = *matches;
frame->todo.Pop(1);
}
break;
case StatementKind::ExpressionStatement:
case Statement::Kind::ExpressionStatement:
if (act->Pos() == 0) {
// { {e :: C, E, F} :: S, H}
// -> { {e :: C, E, F} :: S, H}
frame->todo.Push(global_arena->New<ExpressionAction>(
stmt->GetExpressionStatement().exp));
cast<ExpressionStatement>(*stmt).Exp()));
act->IncrementPos();
} else {
frame->todo.Pop(1);
}
break;
case StatementKind::Assign:
case Statement::Kind::Assign:
if (act->Pos() == 0) {
// { {(lv = e) :: C, E, F} :: S, H}
// -> { {lv :: ([] = e) :: C, E, F} :: S, H}
frame->todo.Push(global_arena->New<LValAction>(stmt->GetAssign().lhs));
frame->todo.Push(
global_arena->New<LValAction>(cast<Assign>(*stmt).Lhs()));
act->IncrementPos();
} else if (act->Pos() == 1) {
// { { a :: ([] = e) :: C, E, F} :: S, H}
// -> { { e :: (a = []) :: C, E, F} :: S, H}
frame->todo.Push(
global_arena->New<ExpressionAction>(stmt->GetAssign().rhs));
global_arena->New<ExpressionAction>(cast<Assign>(*stmt).Rhs()));
act->IncrementPos();
} else if (act->Pos() == 2) {
// { { v :: (a = []) :: C, E, F} :: S, H}
// -> { { C, E, F} :: S, H(a := v)}
auto pat = act->Results()[0];
auto val = act->Results()[1];
PatternAssignment(pat, val, stmt->line_num);
PatternAssignment(pat, val, stmt->LineNumber());
frame->todo.Pop(1);
}
break;
case StatementKind::If:
case Statement::Kind::If:
if (act->Pos() == 0) {
// { {(if (e) then_stmt else else_stmt) :: C, E, F} :: S, H}
// -> { { e :: (if ([]) then_stmt else else_stmt) :: C, E, F} :: S, H}
frame->todo.Push(
global_arena->New<ExpressionAction>(stmt->GetIf().cond));
global_arena->New<ExpressionAction>(cast<If>(*stmt).Cond()));
act->IncrementPos();
} else if (cast<BoolValue>(*act->Results()[0]).Val()) {
// { {true :: if ([]) then_stmt else else_stmt :: C, E, F} ::
@@ -1043,48 +1045,48 @@ void StepStmt() {
// -> { { then_stmt :: C, E, F } :: S, H}
frame->todo.Pop(1);
frame->todo.Push(
global_arena->New<StatementAction>(stmt->GetIf().then_stmt));
} else if (stmt->GetIf().else_stmt) {
global_arena->New<StatementAction>(cast<If>(*stmt).ThenStmt()));
} else if (cast<If>(*stmt).ElseStmt()) {
// { {false :: if ([]) then_stmt else else_stmt :: C, E, F} ::
// S, H}
// -> { { else_stmt :: C, E, F } :: S, H}
frame->todo.Pop(1);
frame->todo.Push(
global_arena->New<StatementAction>(stmt->GetIf().else_stmt));
global_arena->New<StatementAction>(cast<If>(*stmt).ElseStmt()));
} else {
frame->todo.Pop(1);
}
break;
case StatementKind::Return:
case Statement::Kind::Return:
if (act->Pos() == 0) {
// { {return e :: C, E, F} :: S, H}
// -> { {e :: return [] :: C, E, F} :: S, H}
frame->todo.Push(
global_arena->New<ExpressionAction>(stmt->GetReturn().exp));
global_arena->New<ExpressionAction>(cast<Return>(*stmt).Exp()));
act->IncrementPos();
} else {
// { {v :: return [] :: C, E, F} :: {C', E', F'} :: S, H}
// -> { {v :: C', E', F'} :: S, H}
const Value* ret_val = CopyVal(act->Results()[0], stmt->line_num);
DeallocateLocals(stmt->line_num, frame);
const Value* ret_val = CopyVal(act->Results()[0], stmt->LineNumber());
DeallocateLocals(stmt->LineNumber(), frame);
state->stack.Pop(1);
frame = state->stack.Top();
frame->todo.Push(global_arena->New<ValAction>(ret_val));
}
break;
case StatementKind::Sequence:
case Statement::Kind::Sequence:
CHECK(act->Pos() == 0);
// { { (s1,s2) :: C, E, F} :: S, H}
// -> { { s1 :: s2 :: C, E, F} :: S, H}
frame->todo.Pop(1);
if (stmt->GetSequence().next) {
if (cast<Sequence>(*stmt).Next()) {
frame->todo.Push(
global_arena->New<StatementAction>(stmt->GetSequence().next));
global_arena->New<StatementAction>(cast<Sequence>(*stmt).Next()));
}
frame->todo.Push(
global_arena->New<StatementAction>(stmt->GetSequence().stmt));
global_arena->New<StatementAction>(cast<Sequence>(*stmt).Stmt()));
break;
case StatementKind::Continuation: {
case Statement::Kind::Continuation: {
CHECK(act->Pos() == 0);
// Create a continuation object by creating a frame similar the
// way one is created in a function call.
@@ -1094,10 +1096,10 @@ void StepStmt() {
scopes.Push(scope);
Stack<Action*> todo;
todo.Push(global_arena->New<StatementAction>(
Statement::MakeReturn(stmt->line_num, nullptr,
/*is_omitted_exp=*/true)));
global_arena->New<Return>(stmt->LineNumber(), nullptr,
/*is_omitted_exp=*/true)));
todo.Push(
global_arena->New<StatementAction>(stmt->GetContinuation().body));
global_arena->New<StatementAction>(cast<Continuation>(*stmt).Body()));
Frame* continuation_frame =
global_arena->New<Frame>("__continuation", scopes, todo);
Address continuation_address =
@@ -1107,25 +1109,26 @@ void StepStmt() {
continuation_frame->continuation = continuation_address;
// Bind the continuation object to the continuation variable
frame->scopes.Top()->values.Set(
stmt->GetContinuation().continuation_variable, continuation_address);
cast<Continuation>(*stmt).ContinuationVariable(),
continuation_address);
// Pop the continuation statement.
frame->todo.Pop();
break;
}
case StatementKind::Run:
case Statement::Kind::Run:
if (act->Pos() == 0) {
// Evaluate the argument of the run statement.
frame->todo.Push(
global_arena->New<ExpressionAction>(stmt->GetRun().argument));
global_arena->New<ExpressionAction>(cast<Run>(*stmt).Argument()));
act->IncrementPos();
} else {
frame->todo.Pop(1);
// Push an expression statement action to ignore the result
// value from the continuation.
Action* ignore_result = global_arena->New<StatementAction>(
Statement::MakeExpressionStatement(
stmt->line_num,
global_arena->New<TupleLiteral>(stmt->line_num)));
global_arena->New<ExpressionStatement>(
stmt->LineNumber(),
global_arena->New<TupleLiteral>(stmt->LineNumber())));
frame->todo.Push(ignore_result);
// Push the continuation onto the current stack.
const std::vector<Frame*>& continuation_vector =
@@ -1136,7 +1139,7 @@ void StepStmt() {
}
}
break;
case StatementKind::Await:
case Statement::Kind::Await:
CHECK(act->Pos() == 0);
// Pause the current continuation
frame->todo.Pop();
@@ -1147,7 +1150,7 @@ void StepStmt() {
// Update the continuation with the paused stack.
state->heap.Write(*paused.back()->continuation,
global_arena->New<ContinuationValue>(paused),
stmt->line_num);
stmt->LineNumber());
break;
}
}