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Merged
merged 1 commit into from
Jan 8, 2025
Merged

Add support for quoted field selectors. #1150

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17 changes: 12 additions & 5 deletions parser/internal/Cel.g4
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
Expand Down Expand Up @@ -52,16 +52,17 @@ unary

member
: primary # PrimaryExpr
| member op='.' (opt='?')? id=IDENTIFIER # Select
| member op='.' (opt='?')? id=escapeIdent # Select
| member op='.' id=IDENTIFIER open='(' args=exprList? ')' # MemberCall
| member op='[' (opt='?')? index=expr ']' # Index
;

primary
: leadingDot='.'? id=IDENTIFIER (op='(' args=exprList? ')')? # IdentOrGlobalCall
: leadingDot='.'? id=IDENTIFIER # Ident
| leadingDot='.'? id=IDENTIFIER (op='(' args=exprList? ')') # GlobalCall
| '(' e=expr ')' # Nested
| op='[' elems=listInit? ','? ']' # CreateList
| op='{' entries=mapInitializerList? ','? '}' # CreateStruct
| op='{' entries=mapInitializerList? ','? '}' # CreateMap
| leadingDot='.'? ids+=IDENTIFIER (ops+='.' ids+=IDENTIFIER)*
op='{' entries=fieldInitializerList? ','? '}' # CreateMessage
| literal # ConstantLiteral
Expand All @@ -80,13 +81,18 @@ fieldInitializerList
;

optField
: (opt='?')? id=IDENTIFIER
: (opt='?')? escapeIdent
;

mapInitializerList
: keys+=optExpr cols+=':' values+=expr (',' keys+=optExpr cols+=':' values+=expr)*
;

escapeIdent
: id=IDENTIFIER # SimpleIdentifier
| id=ESC_IDENTIFIER # EscapedIdentifier
;

optExpr
: (opt='?')? e=expr
;
Expand Down Expand Up @@ -198,3 +204,4 @@ STRING
BYTES : ('b' | 'B') STRING;

IDENTIFIER : (LETTER | '_') ( LETTER | DIGIT | '_')*;
ESC_IDENTIFIER : '`' (LETTER | DIGIT | '_' | '.' | '-' | '/' | ' ')+ '`';
6 changes: 6 additions & 0 deletions parser/options.h
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,12 @@ struct ParserOptions final {

// Enable hidden accumulator variable '@result' for builtin comprehensions.
bool enable_hidden_accumulator_var = false;

// Enables support for identifier quoting syntax:
// "message.`skewer-case-field`"
//
// Limited to field specifiers in select and message creation.
bool enable_quoted_identifiers = false;
};

} // namespace cel
Expand Down
126 changes: 83 additions & 43 deletions parser/parser.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -608,8 +608,18 @@ class ParserVisitor final : public CelBaseVisitor,
absl::string_view accu_var,
const cel::MacroRegistry& macro_registry,
bool add_macro_calls = false,
bool enable_optional_syntax = false);
~ParserVisitor() override;
bool enable_optional_syntax = false,
bool enable_quoted_identifiers = false)
: source_(source),
factory_(source_, accu_var),
macro_registry_(macro_registry),
recursion_depth_(0),
max_recursion_depth_(max_recursion_depth),
add_macro_calls_(add_macro_calls),
enable_optional_syntax_(enable_optional_syntax),
enable_quoted_identifiers_(enable_quoted_identifiers) {}

~ParserVisitor() override = default;

std::any visit(antlr4::tree::ParseTree* tree) override;

Expand All @@ -630,13 +640,13 @@ class ParserVisitor final : public CelBaseVisitor,
CelParser::FieldInitializerListContext* ctx) override;
std::vector<StructExprField> visitFields(
CelParser::FieldInitializerListContext* ctx);
std::any visitIdentOrGlobalCall(
CelParser::IdentOrGlobalCallContext* ctx) override;
std::any visitGlobalCall(CelParser::GlobalCallContext* ctx) override;
std::any visitIdent(CelParser::IdentContext* ctx) override;
std::any visitNested(CelParser::NestedContext* ctx) override;
std::any visitCreateList(CelParser::CreateListContext* ctx) override;
std::vector<ListExprElement> visitList(CelParser::ListInitContext* ctx);
std::vector<Expr> visitList(CelParser::ExprListContext* ctx);
std::any visitCreateStruct(CelParser::CreateStructContext* ctx) override;
std::any visitCreateMap(CelParser::CreateMapContext* ctx) override;
std::any visitConstantLiteral(
CelParser::ConstantLiteralContext* ctx) override;
std::any visitPrimaryExpr(CelParser::PrimaryExprContext* ctx) override;
Expand Down Expand Up @@ -691,6 +701,8 @@ class ParserVisitor final : public CelBaseVisitor,
Expr target, std::vector<Expr> args);
std::string ExtractQualifiedName(antlr4::ParserRuleContext* ctx,
const Expr& e);

std::string NormalizeIdentifier(CelParser::EscapeIdentContext* ctx);
// Attempt to unnest parse context.
//
// Walk the parse tree to the first complex term to reduce recursive depth in
Expand All @@ -705,24 +717,9 @@ class ParserVisitor final : public CelBaseVisitor,
const int max_recursion_depth_;
const bool add_macro_calls_;
const bool enable_optional_syntax_;
const bool enable_quoted_identifiers_;
};

ParserVisitor::ParserVisitor(const cel::Source& source,
const int max_recursion_depth,
absl::string_view accu_var,
const cel::MacroRegistry& macro_registry,
const bool add_macro_calls,
bool enable_optional_syntax)
: source_(source),
factory_(source_, accu_var),
macro_registry_(macro_registry),
recursion_depth_(0),
max_recursion_depth_(max_recursion_depth),
add_macro_calls_(add_macro_calls),
enable_optional_syntax_(enable_optional_syntax) {}

ParserVisitor::~ParserVisitor() {}

template <typename T, typename = std::enable_if_t<
std::is_base_of<antlr4::tree::ParseTree, T>::value>>
T* tree_as(antlr4::tree::ParseTree* tree) {
Expand Down Expand Up @@ -771,8 +768,8 @@ std::any ParserVisitor::visit(antlr4::tree::ParseTree* tree) {
return visitCreateList(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateMessageContext>(tree)) {
return visitCreateMessage(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateStructContext>(tree)) {
return visitCreateStruct(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateMapContext>(tree)) {
return visitCreateMap(ctx);
}

if (tree) {
Expand All @@ -788,13 +785,14 @@ std::any ParserVisitor::visitPrimaryExpr(CelParser::PrimaryExprContext* pctx) {
CelParser::PrimaryContext* primary = pctx->primary();
if (auto* ctx = tree_as<CelParser::NestedContext>(primary)) {
return visitNested(ctx);
} else if (auto* ctx =
tree_as<CelParser::IdentOrGlobalCallContext>(primary)) {
return visitIdentOrGlobalCall(ctx);
} else if (auto* ctx = tree_as<CelParser::IdentContext>(primary)) {
return visitIdent(ctx);
} else if (auto* ctx = tree_as<CelParser::GlobalCallContext>(primary)) {
return visitGlobalCall(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateListContext>(primary)) {
return visitCreateList(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateStructContext>(primary)) {
return visitCreateStruct(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateMapContext>(primary)) {
return visitCreateMap(ctx);
} else if (auto* ctx = tree_as<CelParser::CreateMessageContext>(primary)) {
return visitCreateMessage(ctx);
} else if (auto* ctx = tree_as<CelParser::ConstantLiteralContext>(primary)) {
Expand Down Expand Up @@ -1013,14 +1011,33 @@ std::any ParserVisitor::visitNegate(CelParser::NegateContext* ctx) {
GlobalCallOrMacro(op_id, CelOperator::NEGATE, std::move(target)));
}

std::string ParserVisitor::NormalizeIdentifier(
CelParser::EscapeIdentContext* ctx) {
if (auto* raw_id = tree_as<CelParser::SimpleIdentifierContext>(ctx); raw_id) {
return raw_id->id->getText();
}
if (auto* escaped_id = tree_as<CelParser::EscapedIdentifierContext>(ctx);
escaped_id) {
if (!enable_quoted_identifiers_) {
factory_.ReportError(SourceRangeFromParserRuleContext(ctx),
"unsupported syntax '`'");
}
auto escaped_id_text = escaped_id->id->getText();
return escaped_id_text.substr(1, escaped_id_text.size() - 2);
}

// Fallthrough might occur if the parser is in an error state.
return "";
}

std::any ParserVisitor::visitSelect(CelParser::SelectContext* ctx) {
auto operand = ExprFromAny(visit(ctx->member()));
// Handle the error case where no valid identifier is specified.
if (!ctx->id || !ctx->op) {
return ExprToAny(factory_.NewUnspecified(
factory_.NextId(SourceRangeFromParserRuleContext(ctx))));
}
auto id = ctx->id->getText();
auto id = NormalizeIdentifier(ctx->id);
if (ctx->opt != nullptr) {
if (!enable_optional_syntax_) {
return ExprToAny(factory_.ReportError(
Expand Down Expand Up @@ -1108,28 +1125,30 @@ std::vector<StructExprField> ParserVisitor::visitFields(
// This is the result of a syntax error detected elsewhere.
return res;
}
const auto* f = ctx->fields[i];
if (f->id == nullptr) {
auto* f = ctx->fields[i];
if (!f->escapeIdent()) {
ABSL_DCHECK(HasErrored());
// This is the result of a syntax error detected elsewhere.
return res;
}

std::string id = NormalizeIdentifier(f->escapeIdent());

int64_t init_id = factory_.NextId(SourceRangeFromToken(ctx->cols[i]));
if (!enable_optional_syntax_ && f->opt) {
factory_.ReportError(SourceRangeFromParserRuleContext(ctx),
"unsupported syntax '?'");
continue;
}
auto value = ExprFromAny(visit(ctx->values[i]));
res.push_back(factory_.NewStructField(init_id, f->id->getText(),
res.push_back(factory_.NewStructField(init_id, std::move(id),
std::move(value), f->opt != nullptr));
}

return res;
}

std::any ParserVisitor::visitIdentOrGlobalCall(
CelParser::IdentOrGlobalCallContext* ctx) {
std::any ParserVisitor::visitIdent(CelParser::IdentContext* ctx) {
std::string ident_name;
if (ctx->leadingDot) {
ident_name = ".";
Expand All @@ -1138,23 +1157,43 @@ std::any ParserVisitor::visitIdentOrGlobalCall(
return ExprToAny(factory_.NewUnspecified(
factory_.NextId(SourceRangeFromParserRuleContext(ctx))));
}
// check if ID is in reserved identifiers
if (cel::internal::LexisIsReserved(ctx->id->getText())) {
return ExprToAny(factory_.ReportError(
SourceRangeFromParserRuleContext(ctx),
absl::StrFormat("reserved identifier: %s", ctx->id->getText())));
}
// check if ID is in reserved identifiers

ident_name += ctx->id->getText();
if (ctx->op) {
int64_t op_id = factory_.NextId(SourceRangeFromToken(ctx->op));
auto args = visitList(ctx->args);
return ExprToAny(
GlobalCallOrMacroImpl(op_id, std::move(ident_name), std::move(args)));
}

return ExprToAny(factory_.NewIdent(
factory_.NextId(SourceRangeFromToken(ctx->id)), std::move(ident_name)));
}

std::any ParserVisitor::visitGlobalCall(CelParser::GlobalCallContext* ctx) {
std::string ident_name;
if (ctx->leadingDot) {
ident_name = ".";
}
if (!ctx->id || !ctx->op) {
return ExprToAny(factory_.NewUnspecified(
factory_.NextId(SourceRangeFromParserRuleContext(ctx))));
}
// check if ID is in reserved identifiers
if (cel::internal::LexisIsReserved(ctx->id->getText())) {
return ExprToAny(factory_.ReportError(
SourceRangeFromParserRuleContext(ctx),
absl::StrFormat("reserved identifier: %s", ctx->id->getText())));
}

ident_name += ctx->id->getText();

int64_t op_id = factory_.NextId(SourceRangeFromToken(ctx->op));
auto args = visitList(ctx->args);
return ExprToAny(
GlobalCallOrMacroImpl(op_id, std::move(ident_name), std::move(args)));
}

std::any ParserVisitor::visitNested(CelParser::NestedContext* ctx) {
return visit(ctx->e);
}
Expand Down Expand Up @@ -1197,7 +1236,7 @@ std::vector<Expr> ParserVisitor::visitList(CelParser::ExprListContext* ctx) {
return rv;
}

std::any ParserVisitor::visitCreateStruct(CelParser::CreateStructContext* ctx) {
std::any ParserVisitor::visitCreateMap(CelParser::CreateMapContext* ctx) {
int64_t struct_id = factory_.NextId(SourceRangeFromToken(ctx->op));
std::vector<MapExprEntry> entries;
if (ctx->entries) {
Expand Down Expand Up @@ -1629,7 +1668,8 @@ absl::StatusOr<ParseResult> ParseImpl(const cel::Source& source,
}
ParserVisitor visitor(source, options.max_recursion_depth, accu_var,
registry, options.add_macro_calls,
options.enable_optional_syntax);
options.enable_optional_syntax,
options.enable_quoted_identifiers);

lexer.removeErrorListeners();
parser.removeErrorListeners();
Expand Down
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