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copybara-service merged 1 commit into from
Jul 28, 2026
Merged

Avoid duplicating complex expressions in optional macros #2167

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102 changes: 63 additions & 39 deletions compiler/optional_test.cc
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -111,11 +111,66 @@ optional.of(
TestCase{
.expr = "optional.of('foo').optMap(x, x)",
.expected_ast = R"(
_?_:_(
__comprehension__(
// Variable
#unused,
// Target
[]~list(dyn),
// Accumulator
@target,
// Init
optional.of(
"foo"~string
)~optional_type(string)^optional_of.hasValue()~bool^optional_hasValue,
)~optional_type(string)^optional_of,
// LoopCondition
false~bool,
// LoopStep
@target~optional_type(string)^@target,
// Result
_?_:_(
@target~optional_type(string)^@target.hasValue()~bool^optional_hasValue,
optional.of(
__comprehension__(
// Variable
#unused,
// Target
[]~list(dyn),
// Accumulator
x,
// Init
@target~optional_type(string)^@target.value()~string^optional_value,
// LoopCondition
false~bool,
// LoopStep
x~string^x,
// Result
x~string^x)~string
)~optional_type(string)^optional_of,
optional.none()~optional_type(string)^optional_none
)~optional_type(string)^conditional)~optional_type(string)
)",
},
TestCase{
.expr = "optional.of('foo').optFlatMap(x, optional.of(x))",
.expected_ast = R"(
__comprehension__(
// Variable
#unused,
// Target
[]~list(dyn),
// Accumulator
@target,
// Init
optional.of(
"foo"~string
)~optional_type(string)^optional_of,
// LoopCondition
false~bool,
// LoopStep
@target~optional_type(string)^@target,
// Result
_?_:_(
@target~optional_type(string)^@target.hasValue()~bool^optional_hasValue,
__comprehension__(
// Variable
#unused,
Expand All @@ -124,48 +179,17 @@ _?_:_(
// Accumulator
x,
// Init
optional.of(
"foo"~string
)~optional_type(string)^optional_of.value()~string^optional_value,
@target~optional_type(string)^@target.value()~string^optional_value,
// LoopCondition
false~bool,
// LoopStep
x~string^x,
// Result
x~string^x)~string
)~optional_type(string)^optional_of,
optional.none()~optional_type(string)^optional_none
)~optional_type(string)^conditional
)",
},
TestCase{
.expr = "optional.of('foo').optFlatMap(x, optional.of(x))",
.expected_ast = R"(
_?_:_(
optional.of(
"foo"~string
)~optional_type(string)^optional_of.hasValue()~bool^optional_hasValue,
__comprehension__(
// Variable
#unused,
// Target
[]~list(dyn),
// Accumulator
x,
// Init
optional.of(
"foo"~string
)~optional_type(string)^optional_of.value()~string^optional_value,
// LoopCondition
false~bool,
// LoopStep
x~string^x,
// Result
optional.of(
x~string^x
)~optional_type(string)^optional_of)~optional_type(string),
optional.none()~optional_type(string)^optional_none
)~optional_type(string)^conditional
optional.of(
x~string^x
)~optional_type(string)^optional_of)~optional_type(string),
optional.none()~optional_type(string)^optional_none
)~optional_type(string)^conditional)~optional_type(string)
)",
},
TestCase{
Expand Down
92 changes: 76 additions & 16 deletions parser/macro.cc
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,8 @@ namespace cel {

namespace {

constexpr absl::string_view kOptionalMapVar = "@target";

using google::api::expr::common::CelOperator;

bool IsSimpleIdentifier(const Expr& expr) {
Expand Down Expand Up @@ -315,20 +317,50 @@ absl::optional<Expr> ExpandOptMapMacro(MacroExprFactory& factory, Expr& target,
}
auto var_name = args[0].ident_expr().name();

auto target_copy = factory.Copy(target);
std::vector<Expr> call_args;
call_args.reserve(3);
call_args.push_back(factory.NewMemberCall("hasValue", std::move(target)));
if (target.has_ident_expr()) {
auto target_copy = factory.Copy(target);
std::vector<Expr> call_args;
call_args.reserve(3);
call_args.push_back(factory.NewMemberCall("hasValue", std::move(target)));
auto iter_range = factory.NewList();
auto accu_init = factory.NewMemberCall("value", std::move(target_copy));
auto condition = factory.NewBoolConst(false);
auto fold = factory.NewComprehension(
"#unused", std::move(iter_range), std::move(var_name),
std::move(accu_init), std::move(condition), std::move(args[0]),
std::move(args[1]));
call_args.push_back(factory.NewCall("optional.of", std::move(fold)));
call_args.push_back(factory.NewCall("optional.none"));
return factory.NewCall(CelOperator::CONDITIONAL, std::move(call_args));
}

// If the target is complex, use an internal bind expression to avoid
// repeating it and blowing up the AST in the expansion
auto tmp = factory.NewIdent(kOptionalMapVar);
auto tmp_copy = factory.Copy(tmp);

auto iter_range = factory.NewList();
auto accu_init = factory.NewMemberCall("value", std::move(target_copy));
auto accu_init = factory.NewMemberCall("value", std::move(tmp_copy));
auto condition = factory.NewBoolConst(false);
auto loop_step = std::move(args[0]);
auto fold = factory.NewComprehension(
"#unused", std::move(iter_range), std::move(var_name),
std::move(accu_init), std::move(condition), std::move(args[0]),
std::move(accu_init), std::move(condition), std::move(loop_step),
std::move(args[1]));
std::vector<Expr> call_args;
call_args.reserve(3);
call_args.push_back(factory.NewMemberCall("hasValue", std::move(tmp)));
call_args.push_back(factory.NewCall("optional.of", std::move(fold)));
call_args.push_back(factory.NewCall("optional.none"));
return factory.NewCall(CelOperator::CONDITIONAL, std::move(call_args));
auto result = factory.NewCall(CelOperator::CONDITIONAL, std::move(call_args));

iter_range = factory.NewList();
accu_init = std::move(target);
condition = factory.NewBoolConst(false);
loop_step = factory.NewIdent(kOptionalMapVar);
return factory.NewComprehension(
"#unused", std::move(iter_range), kOptionalMapVar, std::move(accu_init),
std::move(condition), loop_step, std::move(result));
}

Macro MakeOptMapMacro() {
Expand All @@ -354,19 +386,47 @@ absl::optional<Expr> ExpandOptFlatMapMacro(MacroExprFactory& factory,
}
auto var_name = args[0].ident_expr().name();

auto target_copy = factory.Copy(target);
std::vector<Expr> call_args;
call_args.reserve(3);
call_args.push_back(factory.NewMemberCall("hasValue", std::move(target)));
if (target.has_ident_expr()) {
auto target_copy = factory.Copy(target);
std::vector<Expr> call_args;
call_args.reserve(3);
call_args.push_back(factory.NewMemberCall("hasValue", std::move(target)));
auto iter_range = factory.NewList();
auto accu_init = factory.NewMemberCall("value", std::move(target_copy));
auto condition = factory.NewBoolConst(false);
call_args.push_back(factory.NewComprehension(
"#unused", std::move(iter_range), std::move(var_name),
std::move(accu_init), std::move(condition), std::move(args[0]),
std::move(args[1])));
call_args.push_back(factory.NewCall("optional.none"));
return factory.NewCall(CelOperator::CONDITIONAL, std::move(call_args));
}

auto tmp = factory.NewIdent(kOptionalMapVar);
auto tmp_copy = factory.Copy(tmp);

auto iter_range = factory.NewList();
auto accu_init = factory.NewMemberCall("value", std::move(target_copy));
auto accu_init = factory.NewMemberCall("value", std::move(tmp_copy));
auto condition = factory.NewBoolConst(false);
call_args.push_back(factory.NewComprehension(
auto loop_step = std::move(args[0]);
auto inner = factory.NewComprehension(
"#unused", std::move(iter_range), std::move(var_name),
std::move(accu_init), std::move(condition), std::move(args[0]),
std::move(args[1])));
std::move(accu_init), std::move(condition), std::move(loop_step),
std::move(args[1]));
std::vector<Expr> call_args;
call_args.reserve(3);
call_args.push_back(factory.NewMemberCall("hasValue", std::move(tmp)));
call_args.push_back(std::move(inner));
call_args.push_back(factory.NewCall("optional.none"));
return factory.NewCall(CelOperator::CONDITIONAL, std::move(call_args));
auto result = factory.NewCall(CelOperator::CONDITIONAL, std::move(call_args));

iter_range = factory.NewList();
accu_init = std::move(target);
condition = factory.NewBoolConst(false);
loop_step = factory.NewIdent(kOptionalMapVar);
return factory.NewComprehension(
"#unused", std::move(iter_range), kOptionalMapVar, std::move(accu_init),
std::move(condition), loop_step, std::move(result));
}

Macro MakeOptFlatMapMacro() {
Expand Down
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