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Fix issue 246 (#247)
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* Add `parse_expression` with one argument in preparation to fix #246.

* Fix issue #246: `func(n1 + n2, n3)` runs as if `func(n1, n2 + n3)`

* Simplify parser for an expression enclosed by parentheses.
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@kubo
kubo authored Dec 4, 2022
1 parent edc1779 commit d462b9f
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Showing 6 changed files with 128 additions and 152 deletions.
2 changes: 0 additions & 2 deletions include/inja/function_storage.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -62,8 +62,6 @@ class FunctionStorage {
Super,
Join,
Callback,
ParenLeft,
ParenRight,
None,
};

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2 changes: 1 addition & 1 deletion include/inja/node.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -148,7 +148,7 @@ class FunctionNode : public ExpressionNode {
CallbackFunction callback;

explicit FunctionNode(std::string_view name, size_t pos)
: ExpressionNode(pos), precedence(8), associativity(Associativity::Left), operation(Op::Callback), name(name), number_args(1) {}
: ExpressionNode(pos), precedence(8), associativity(Associativity::Left), operation(Op::Callback), name(name), number_args(0) {}
explicit FunctionNode(Op operation, size_t pos): ExpressionNode(pos), operation(operation), number_args(1) {
switch (operation) {
case Op::Not: {
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133 changes: 62 additions & 71 deletions include/inja/parser.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,9 @@ namespace inja {
* \brief Class for parsing an inja Template.
*/
class Parser {
using Arguments = std::vector<std::shared_ptr<ExpressionNode>>;
using OperatorStack = std::stack<std::shared_ptr<FunctionNode>>;

const ParserConfig& config;

Lexer lexer;
Expand All @@ -31,18 +34,11 @@ class Parser {
Token tok, peek_tok;
bool have_peek_tok {false};

size_t current_paren_level {0};
size_t current_bracket_level {0};
size_t current_brace_level {0};

std::string_view literal_start;

BlockNode* current_block {nullptr};
ExpressionListNode* current_expression_list {nullptr};
std::stack<std::pair<FunctionNode*, size_t>> function_stack;
std::vector<std::shared_ptr<ExpressionNode>> arguments;

std::stack<std::shared_ptr<FunctionNode>> operator_stack;
std::stack<IfStatementNode*> if_statement_stack;
std::stack<ForStatementNode*> for_statement_stack;
std::stack<BlockStatementNode*> block_statement_stack;
Expand All @@ -67,12 +63,12 @@ class Parser {
}
}

inline void add_literal(const char* content_ptr) {
inline void add_literal(Arguments &arguments, const char* content_ptr) {
std::string_view data_text(literal_start.data(), tok.text.data() - literal_start.data() + tok.text.size());
arguments.emplace_back(std::make_shared<LiteralNode>(data_text, data_text.data() - content_ptr));
}

inline void add_operator() {
inline void add_operator(Arguments &arguments, OperatorStack &operator_stack) {
auto function = operator_stack.top();
operator_stack.pop();

Expand Down Expand Up @@ -140,19 +136,29 @@ class Parser {
}

bool parse_expression(Template& tmpl, Token::Kind closing) {
while (tok.kind != closing && tok.kind != Token::Kind::Eof) {
current_expression_list->root = parse_expression(tmpl);
return tok.kind == closing;
}

std::shared_ptr<ExpressionNode> parse_expression(Template& tmpl) {
size_t current_bracket_level {0};
size_t current_brace_level {0};
Arguments arguments;
OperatorStack operator_stack;

while (tok.kind != Token::Kind::Eof) {
// Literals
switch (tok.kind) {
case Token::Kind::String: {
if (current_brace_level == 0 && current_bracket_level == 0) {
literal_start = tok.text;
add_literal(tmpl.content.c_str());
add_literal(arguments, tmpl.content.c_str());
}
} break;
case Token::Kind::Number: {
if (current_brace_level == 0 && current_bracket_level == 0) {
literal_start = tok.text;
add_literal(tmpl.content.c_str());
add_literal(arguments, tmpl.content.c_str());
}
} break;
case Token::Kind::LeftBracket: {
Expand All @@ -174,7 +180,7 @@ class Parser {

current_bracket_level -= 1;
if (current_brace_level == 0 && current_bracket_level == 0) {
add_literal(tmpl.content.c_str());
add_literal(arguments, tmpl.content.c_str());
}
} break;
case Token::Kind::RightBrace: {
Expand All @@ -184,7 +190,7 @@ class Parser {

current_brace_level -= 1;
if (current_brace_level == 0 && current_bracket_level == 0) {
add_literal(tmpl.content.c_str());
add_literal(arguments, tmpl.content.c_str());
}
} break;
case Token::Kind::Id: {
Expand All @@ -195,7 +201,7 @@ class Parser {
tok.text == static_cast<decltype(tok.text)>("null")) {
if (current_brace_level == 0 && current_bracket_level == 0) {
literal_start = tok.text;
add_literal(tmpl.content.c_str());
add_literal(arguments, tmpl.content.c_str());
}

// Operator
Expand All @@ -204,8 +210,30 @@ class Parser {

// Functions
} else if (peek_tok.kind == Token::Kind::LeftParen) {
operator_stack.emplace(std::make_shared<FunctionNode>(static_cast<std::string>(tok.text), tok.text.data() - tmpl.content.c_str()));
function_stack.emplace(operator_stack.top().get(), current_paren_level);
auto func = std::make_shared<FunctionNode>(tok.text, tok.text.data() - tmpl.content.c_str());
get_next_token();
do {
get_next_token();
auto expr = parse_expression(tmpl);
if (!expr) {
break;
}
func->number_args += 1;
func->arguments.emplace_back(expr);
} while (tok.kind == Token::Kind::Comma);
if (tok.kind != Token::Kind::RightParen) {
throw_parser_error("expected right parenthesis, got '" + tok.describe() + "'");
}

auto function_data = function_storage.find_function(func->name, func->number_args);
if (function_data.operation == FunctionStorage::Operation::None) {
throw_parser_error("unknown function " + func->name);
}
func->operation = function_data.operation;
if (function_data.operation == FunctionStorage::Operation::Callback) {
func->callback = function_data.callback;
}
arguments.emplace_back(func);

// Variables
} else {
Expand Down Expand Up @@ -291,20 +319,15 @@ class Parser {

while (!operator_stack.empty() &&
((operator_stack.top()->precedence > function_node->precedence) ||
(operator_stack.top()->precedence == function_node->precedence && function_node->associativity == FunctionNode::Associativity::Left)) &&
(operator_stack.top()->operation != FunctionStorage::Operation::ParenLeft)) {
add_operator();
(operator_stack.top()->precedence == function_node->precedence && function_node->associativity == FunctionNode::Associativity::Left))) {
add_operator(arguments, operator_stack);
}

operator_stack.emplace(function_node);
} break;
case Token::Kind::Comma: {
if (current_brace_level == 0 && current_bracket_level == 0) {
if (function_stack.empty()) {
throw_parser_error("unexpected ','");
}

function_stack.top().first->number_args += 1;
goto break_loop;
}
} break;
case Token::Kind::Colon: {
Expand All @@ -313,64 +336,36 @@ class Parser {
}
} break;
case Token::Kind::LeftParen: {
current_paren_level += 1;
operator_stack.emplace(std::make_shared<FunctionNode>(FunctionStorage::Operation::ParenLeft, tok.text.data() - tmpl.content.c_str()));

get_peek_token();
if (peek_tok.kind == Token::Kind::RightParen) {
if (!function_stack.empty() && function_stack.top().second == current_paren_level - 1) {
function_stack.top().first->number_args = 0;
}
}
} break;
case Token::Kind::RightParen: {
current_paren_level -= 1;
while (!operator_stack.empty() && operator_stack.top()->operation != FunctionStorage::Operation::ParenLeft) {
add_operator();
get_next_token();
auto expr = parse_expression(tmpl);
if (tok.kind != Token::Kind::RightParen) {
throw_parser_error("expected right parenthesis, got '" + tok.describe() + "'");
}

if (!operator_stack.empty() && operator_stack.top()->operation == FunctionStorage::Operation::ParenLeft) {
operator_stack.pop();
if (!expr) {
throw_parser_error("empty expression in parentheses");
}

if (!function_stack.empty() && function_stack.top().second == current_paren_level) {
auto func = function_stack.top().first;
auto function_data = function_storage.find_function(func->name, func->number_args);
if (function_data.operation == FunctionStorage::Operation::None) {
throw_parser_error("unknown function " + func->name);
}
func->operation = function_data.operation;
if (function_data.operation == FunctionStorage::Operation::Callback) {
func->callback = function_data.callback;
}

if (operator_stack.empty()) {
throw_parser_error("internal error at function " + func->name);
}

add_operator();
function_stack.pop();
}
}
arguments.emplace_back(expr);
} break;
default:
break;
goto break_loop;
}

get_next_token();
}

break_loop:
while (!operator_stack.empty()) {
add_operator();
add_operator(arguments, operator_stack);
}

std::shared_ptr<ExpressionNode> expr;
if (arguments.size() == 1) {
current_expression_list->root = arguments[0];
expr = arguments[0];
arguments = {};
} else if (arguments.size() > 1) {
throw_parser_error("malformed expression");
}

return true;
return expr;
}

bool parse_statement(Template& tmpl, Token::Kind closing, std::string_view path) {
Expand Down Expand Up @@ -604,10 +599,6 @@ class Parser {
current_expression_list = expression_list_node.get();

if (!parse_expression(tmpl, Token::Kind::ExpressionClose)) {
throw_parser_error("expected expression, got '" + tok.describe() + "'");
}

if (tok.kind != Token::Kind::ExpressionClose) {
throw_parser_error("expected expression close, got '" + tok.describe() + "'");
}
} break;
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2 changes: 0 additions & 2 deletions include/inja/renderer.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -464,8 +464,6 @@ class Renderer : public NodeVisitor {
}
make_result(os.str());
} break;
case Op::ParenLeft:
case Op::ParenRight:
case Op::None:
break;
}
Expand Down
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