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jj/cli/src/template_parser.rs

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// Copyright 2020 The Jujutsu Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::collections::HashMap;
use std::{error, fmt, mem};
use itertools::Itertools as _;
use jj_lib::dsl_util::{collect_similar, StringLiteralParser};
use once_cell::sync::Lazy;
use pest::iterators::{Pair, Pairs};
use pest::pratt_parser::{Assoc, Op, PrattParser};
use pest::Parser;
use pest_derive::Parser;
use thiserror::Error;
#[derive(Parser)]
#[grammar = "template.pest"]
struct TemplateParser;
const STRING_LITERAL_PARSER: StringLiteralParser<Rule> = StringLiteralParser {
content_rule: Rule::string_content,
escape_rule: Rule::string_escape,
};
impl Rule {
fn to_symbol(self) -> Option<&'static str> {
match self {
Rule::EOI => None,
Rule::whitespace => None,
Rule::string_escape => None,
Rule::string_content_char => None,
Rule::string_content => None,
Rule::string_literal => None,
Rule::raw_string_content => None,
Rule::raw_string_literal => None,
Rule::integer_literal => None,
Rule::identifier => None,
Rule::concat_op => Some("++"),
Rule::logical_or_op => Some("||"),
Rule::logical_and_op => Some("&&"),
Rule::logical_not_op => Some("!"),
Rule::negate_op => Some("-"),
Rule::prefix_ops => None,
Rule::infix_ops => None,
Rule::function => None,
Rule::function_arguments => None,
Rule::lambda => None,
Rule::formal_parameters => None,
Rule::primary => None,
Rule::term => None,
Rule::expression => None,
Rule::template => None,
Rule::program => None,
Rule::function_alias_declaration => None,
Rule::alias_declaration => None,
}
}
}
pub type TemplateParseResult<T> = Result<T, TemplateParseError>;
#[derive(Debug, Error)]
#[error("{pest_error}")]
pub struct TemplateParseError {
kind: TemplateParseErrorKind,
pest_error: Box<pest::error::Error<Rule>>,
source: Option<Box<dyn error::Error + Send + Sync>>,
}
#[derive(Clone, Debug, Eq, Error, PartialEq)]
pub enum TemplateParseErrorKind {
#[error("Syntax error")]
SyntaxError,
#[error(r#"Keyword "{name}" doesn't exist"#)]
NoSuchKeyword {
name: String,
candidates: Vec<String>,
},
#[error(r#"Function "{name}" doesn't exist"#)]
NoSuchFunction {
name: String,
candidates: Vec<String>,
},
#[error(r#"Method "{name}" doesn't exist for type "{type_name}""#)]
NoSuchMethod {
type_name: String,
name: String,
candidates: Vec<String>,
},
#[error(r#"Function "{name}": {message}"#)]
InvalidArguments { name: String, message: String },
#[error("Redefinition of function parameter")]
RedefinedFunctionParameter,
#[error("{0}")]
Expression(String),
#[error(r#"Alias "{0}" cannot be expanded"#)]
BadAliasExpansion(String),
#[error(r#"Alias "{0}" expanded recursively"#)]
RecursiveAlias(String),
}
impl TemplateParseError {
pub fn with_span(kind: TemplateParseErrorKind, span: pest::Span<'_>) -> Self {
let message = kind.to_string();
let pest_error = Box::new(pest::error::Error::new_from_span(
pest::error::ErrorVariant::CustomError { message },
span,
));
TemplateParseError {
kind,
pest_error,
source: None,
}
}
pub fn with_source(mut self, source: impl Into<Box<dyn error::Error + Send + Sync>>) -> Self {
self.source = Some(source.into());
self
}
// TODO: migrate all callers to table-based lookup_method()
pub(crate) fn no_such_method(
type_name: impl Into<String>,
function: &FunctionCallNode,
) -> Self {
TemplateParseError::with_span(
TemplateParseErrorKind::NoSuchMethod {
type_name: type_name.into(),
name: function.name.to_owned(),
candidates: vec![],
},
function.name_span,
)
}
pub fn invalid_arguments(function: &FunctionCallNode, message: impl Into<String>) -> Self {
TemplateParseError::with_span(
TemplateParseErrorKind::InvalidArguments {
name: function.name.to_owned(),
message: message.into(),
},
function.args_span,
)
}
pub fn expected_type(expected: &str, actual: &str, span: pest::Span<'_>) -> Self {
let message =
format!(r#"Expected expression of type "{expected}", but actual type is "{actual}""#);
TemplateParseError::expression(message, span)
}
/// Some other expression error.
pub fn expression(message: impl Into<String>, span: pest::Span<'_>) -> Self {
TemplateParseError::with_span(TemplateParseErrorKind::Expression(message.into()), span)
}
pub fn within_alias_expansion(self, id: TemplateAliasId<'_>, span: pest::Span<'_>) -> Self {
TemplateParseError::with_span(
TemplateParseErrorKind::BadAliasExpansion(id.to_string()),
span,
)
.with_source(self)
}
/// If this is a `NoSuchKeyword` error, expands the candidates list with the
/// given `other_keywords`.
pub fn extend_keyword_candidates<I>(mut self, other_keywords: I) -> Self
where
I: IntoIterator,
I::Item: AsRef<str>,
{
if let TemplateParseErrorKind::NoSuchKeyword { name, candidates } = &mut self.kind {
let other_candidates = collect_similar(name, other_keywords);
*candidates = itertools::merge(mem::take(candidates), other_candidates)
.dedup()
.collect();
}
self
}
/// If this is a `NoSuchFunction` error, expands the candidates list with
/// the given `other_functions`.
pub fn extend_function_candidates<I>(mut self, other_functions: I) -> Self
where
I: IntoIterator,
I::Item: AsRef<str>,
{
if let TemplateParseErrorKind::NoSuchFunction { name, candidates } = &mut self.kind {
let other_candidates = collect_similar(name, other_functions);
*candidates = itertools::merge(mem::take(candidates), other_candidates)
.dedup()
.collect();
}
self
}
/// Expands keyword/function candidates with the given aliases.
pub fn extend_alias_candidates(self, aliases_map: &TemplateAliasesMap) -> Self {
self.extend_keyword_candidates(aliases_map.symbol_aliases.keys())
.extend_function_candidates(aliases_map.function_aliases.keys())
}
pub fn kind(&self) -> &TemplateParseErrorKind {
&self.kind
}
/// Original parsing error which typically occurred in an alias expression.
pub fn origin(&self) -> Option<&Self> {
self.source.as_ref().and_then(|e| e.downcast_ref())
}
}
impl From<pest::error::Error<Rule>> for TemplateParseError {
fn from(err: pest::error::Error<Rule>) -> Self {
TemplateParseError {
kind: TemplateParseErrorKind::SyntaxError,
pest_error: Box::new(rename_rules_in_pest_error(err)),
source: None,
}
}
}
fn rename_rules_in_pest_error(err: pest::error::Error<Rule>) -> pest::error::Error<Rule> {
err.renamed_rules(|rule| {
rule.to_symbol()
.map(|sym| format!("`{sym}`"))
.unwrap_or_else(|| format!("<{rule:?}>"))
})
}
/// AST node without type or name checking.
#[derive(Clone, Debug, PartialEq)]
pub struct ExpressionNode<'i> {
pub kind: ExpressionKind<'i>,
pub span: pest::Span<'i>,
}
impl<'i> ExpressionNode<'i> {
fn new(kind: ExpressionKind<'i>, span: pest::Span<'i>) -> Self {
ExpressionNode { kind, span }
}
}
#[derive(Clone, Debug, PartialEq)]
pub enum ExpressionKind<'i> {
Identifier(&'i str),
Boolean(bool),
Integer(i64),
String(String),
Unary(UnaryOp, Box<ExpressionNode<'i>>),
Binary(BinaryOp, Box<ExpressionNode<'i>>, Box<ExpressionNode<'i>>),
Concat(Vec<ExpressionNode<'i>>),
FunctionCall(FunctionCallNode<'i>),
MethodCall(MethodCallNode<'i>),
Lambda(LambdaNode<'i>),
/// Identity node to preserve the span in the source template text.
AliasExpanded(TemplateAliasId<'i>, Box<ExpressionNode<'i>>),
}
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub enum UnaryOp {
/// `!`
LogicalNot,
/// `-`
Negate,
}
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
pub enum BinaryOp {
/// `||`
LogicalOr,
/// `&&`
LogicalAnd,
}
#[derive(Clone, Debug, PartialEq)]
pub struct FunctionCallNode<'i> {
pub name: &'i str,
pub name_span: pest::Span<'i>,
pub args: Vec<ExpressionNode<'i>>,
pub args_span: pest::Span<'i>,
}
#[derive(Clone, Debug, PartialEq)]
pub struct MethodCallNode<'i> {
pub object: Box<ExpressionNode<'i>>,
pub function: FunctionCallNode<'i>,
}
#[derive(Clone, Debug, PartialEq)]
pub struct LambdaNode<'i> {
pub params: Vec<&'i str>,
pub params_span: pest::Span<'i>,
pub body: Box<ExpressionNode<'i>>,
}
fn parse_identifier_or_literal(pair: Pair<Rule>) -> ExpressionKind {
assert_eq!(pair.as_rule(), Rule::identifier);
match pair.as_str() {
"false" => ExpressionKind::Boolean(false),
"true" => ExpressionKind::Boolean(true),
name => ExpressionKind::Identifier(name),
}
}
fn parse_identifier_name(pair: Pair<Rule>) -> TemplateParseResult<&str> {
let span = pair.as_span();
if let ExpressionKind::Identifier(name) = parse_identifier_or_literal(pair) {
Ok(name)
} else {
Err(TemplateParseError::expression("Expected identifier", span))
}
}
fn parse_formal_parameters(params_pair: Pair<Rule>) -> TemplateParseResult<Vec<&str>> {
assert_eq!(params_pair.as_rule(), Rule::formal_parameters);
let params_span = params_pair.as_span();
let params: Vec<_> = params_pair
.into_inner()
.map(parse_identifier_name)
.try_collect()?;
if params.iter().all_unique() {
Ok(params)
} else {
Err(TemplateParseError::with_span(
TemplateParseErrorKind::RedefinedFunctionParameter,
params_span,
))
}
}
fn parse_function_call_node(pair: Pair<Rule>) -> TemplateParseResult<FunctionCallNode> {
assert_eq!(pair.as_rule(), Rule::function);
let mut inner = pair.into_inner();
let name_pair = inner.next().unwrap();
let name_span = name_pair.as_span();
let args_pair = inner.next().unwrap();
let args_span = args_pair.as_span();
assert_eq!(args_pair.as_rule(), Rule::function_arguments);
let name = parse_identifier_name(name_pair)?;
let args = args_pair
.into_inner()
.map(parse_template_node)
.try_collect()?;
Ok(FunctionCallNode {
name,
name_span,
args,
args_span,
})
}
fn parse_lambda_node(pair: Pair<Rule>) -> TemplateParseResult<LambdaNode> {
assert_eq!(pair.as_rule(), Rule::lambda);
let mut inner = pair.into_inner();
let params_pair = inner.next().unwrap();
let params_span = params_pair.as_span();
let body_pair = inner.next().unwrap();
let params = parse_formal_parameters(params_pair)?;
let body = parse_template_node(body_pair)?;
Ok(LambdaNode {
params,
params_span,
body: Box::new(body),
})
}
fn parse_term_node(pair: Pair<Rule>) -> TemplateParseResult<ExpressionNode> {
assert_eq!(pair.as_rule(), Rule::term);
let mut inner = pair.into_inner();
let expr = inner.next().unwrap();
let span = expr.as_span();
let primary = match expr.as_rule() {
Rule::string_literal => {
let text = STRING_LITERAL_PARSER.parse(expr.into_inner());
ExpressionNode::new(ExpressionKind::String(text), span)
}
Rule::raw_string_literal => {
let (content,) = expr.into_inner().collect_tuple().unwrap();
assert_eq!(content.as_rule(), Rule::raw_string_content);
let text = content.as_str().to_owned();
ExpressionNode::new(ExpressionKind::String(text), span)
}
Rule::integer_literal => {
let value = expr.as_str().parse().map_err(|err| {
TemplateParseError::expression("Invalid integer literal", span).with_source(err)
})?;
ExpressionNode::new(ExpressionKind::Integer(value), span)
}
Rule::identifier => ExpressionNode::new(parse_identifier_or_literal(expr), span),
Rule::function => {
let function = parse_function_call_node(expr)?;
ExpressionNode::new(ExpressionKind::FunctionCall(function), span)
}
Rule::lambda => {
let lambda = parse_lambda_node(expr)?;
ExpressionNode::new(ExpressionKind::Lambda(lambda), span)
}
Rule::template => parse_template_node(expr)?,
other => panic!("unexpected term: {other:?}"),
};
inner.try_fold(primary, |object, chain| {
assert_eq!(chain.as_rule(), Rule::function);
let span = object.span.start_pos().span(&chain.as_span().end_pos());
let method = MethodCallNode {
object: Box::new(object),
function: parse_function_call_node(chain)?,
};
Ok(ExpressionNode::new(
ExpressionKind::MethodCall(method),
span,
))
})
}
fn parse_expression_node(pair: Pair<Rule>) -> TemplateParseResult<ExpressionNode> {
assert_eq!(pair.as_rule(), Rule::expression);
static PRATT: Lazy<PrattParser<Rule>> = Lazy::new(|| {
PrattParser::new()
.op(Op::infix(Rule::logical_or_op, Assoc::Left))
.op(Op::infix(Rule::logical_and_op, Assoc::Left))
.op(Op::prefix(Rule::logical_not_op) | Op::prefix(Rule::negate_op))
});
PRATT
.map_primary(parse_term_node)
.map_prefix(|op, rhs| {
let op_kind = match op.as_rule() {
Rule::logical_not_op => UnaryOp::LogicalNot,
Rule::negate_op => UnaryOp::Negate,
r => panic!("unexpected prefix operator rule {r:?}"),
};
let rhs = Box::new(rhs?);
let span = op.as_span().start_pos().span(&rhs.span.end_pos());
let expr = ExpressionKind::Unary(op_kind, rhs);
Ok(ExpressionNode::new(expr, span))
})
.map_infix(|lhs, op, rhs| {
let op_kind = match op.as_rule() {
Rule::logical_or_op => BinaryOp::LogicalOr,
Rule::logical_and_op => BinaryOp::LogicalAnd,
r => panic!("unexpected infix operator rule {r:?}"),
};
let lhs = Box::new(lhs?);
let rhs = Box::new(rhs?);
let span = lhs.span.start_pos().span(&rhs.span.end_pos());
let expr = ExpressionKind::Binary(op_kind, lhs, rhs);
Ok(ExpressionNode::new(expr, span))
})
.parse(pair.into_inner())
}
fn parse_template_node(pair: Pair<Rule>) -> TemplateParseResult<ExpressionNode> {
assert_eq!(pair.as_rule(), Rule::template);
let span = pair.as_span();
let inner = pair.into_inner();
let mut nodes: Vec<_> = inner
.filter_map(|pair| match pair.as_rule() {
Rule::concat_op => None,
Rule::expression => Some(parse_expression_node(pair)),
r => panic!("unexpected template item rule {r:?}"),
})
.try_collect()?;
if nodes.len() == 1 {
Ok(nodes.pop().unwrap())
} else {
Ok(ExpressionNode::new(ExpressionKind::Concat(nodes), span))
}
}
/// Parses text into AST nodes. No type/name checking is made at this stage.
pub fn parse_template(template_text: &str) -> TemplateParseResult<ExpressionNode> {
let mut pairs: Pairs<Rule> = TemplateParser::parse(Rule::program, template_text)?;
let first_pair = pairs.next().unwrap();
if first_pair.as_rule() == Rule::EOI {
let span = first_pair.as_span();
Ok(ExpressionNode::new(ExpressionKind::Concat(vec![]), span))
} else {
parse_template_node(first_pair)
}
}
#[derive(Clone, Debug, Default)]
pub struct TemplateAliasesMap {
symbol_aliases: HashMap<String, String>,
function_aliases: HashMap<String, (Vec<String>, String)>,
}
impl TemplateAliasesMap {
pub fn new() -> Self {
Self::default()
}
pub fn symbol_names(&self) -> impl Iterator<Item = &str> {
self.symbol_aliases.keys().map(|s| s.as_str())
}
/// Adds new substitution rule `decl = defn`.
///
/// Returns error if `decl` is invalid. The `defn` part isn't checked. A bad
/// `defn` will be reported when the alias is substituted.
pub fn insert(
&mut self,
decl: impl AsRef<str>,
defn: impl Into<String>,
) -> TemplateParseResult<()> {
match TemplateAliasDeclaration::parse(decl.as_ref())? {
TemplateAliasDeclaration::Symbol(name) => {
self.symbol_aliases.insert(name, defn.into());
}
TemplateAliasDeclaration::Function(name, params) => {
self.function_aliases.insert(name, (params, defn.into()));
}
}
Ok(())
}
fn get_symbol(&self, name: &str) -> Option<(TemplateAliasId<'_>, &str)> {
self.symbol_aliases
.get_key_value(name)
.map(|(name, defn)| (TemplateAliasId::Symbol(name), defn.as_ref()))
}
fn get_function(&self, name: &str) -> Option<(TemplateAliasId<'_>, &[String], &str)> {
self.function_aliases
.get_key_value(name)
.map(|(name, (params, defn))| {
(
TemplateAliasId::Function(name),
params.as_ref(),
defn.as_ref(),
)
})
}
}
/// Parsed declaration part of alias rule.
#[derive(Clone, Debug)]
enum TemplateAliasDeclaration {
Symbol(String),
Function(String, Vec<String>),
}
impl TemplateAliasDeclaration {
fn parse(source: &str) -> TemplateParseResult<Self> {
let mut pairs = TemplateParser::parse(Rule::alias_declaration, source)?;
let first = pairs.next().unwrap();
match first.as_rule() {
Rule::identifier => {
let name = parse_identifier_name(first)?.to_owned();
Ok(TemplateAliasDeclaration::Symbol(name))
}
Rule::function_alias_declaration => {
let mut inner = first.into_inner();
let name_pair = inner.next().unwrap();
let params_pair = inner.next().unwrap();
let name = parse_identifier_name(name_pair)?.to_owned();
let params = parse_formal_parameters(params_pair)?
.into_iter()
.map(|s| s.to_owned())
.collect();
Ok(TemplateAliasDeclaration::Function(name, params))
}
r => panic!("unexpected alias declaration rule {r:?}"),
}
}
}
/// Borrowed reference to identify alias expression.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum TemplateAliasId<'a> {
Symbol(&'a str),
Function(&'a str),
}
impl fmt::Display for TemplateAliasId<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
TemplateAliasId::Symbol(name) => write!(f, "{name}"),
TemplateAliasId::Function(name) => write!(f, "{name}()"),
}
}
}
/// Expand aliases recursively.
pub fn expand_aliases<'i>(
node: ExpressionNode<'i>,
aliases_map: &'i TemplateAliasesMap,
) -> TemplateParseResult<ExpressionNode<'i>> {
#[derive(Clone, Copy, Debug)]
struct State<'a, 'i> {
aliases_map: &'i TemplateAliasesMap,
aliases_expanding: &'a [TemplateAliasId<'a>],
locals: &'a HashMap<&'a str, ExpressionNode<'i>>,
}
fn expand_defn<'i>(
id: TemplateAliasId<'i>,
defn: &'i str,
locals: &HashMap<&str, ExpressionNode<'i>>,
span: pest::Span<'i>,
state: State<'_, 'i>,
) -> TemplateParseResult<ExpressionNode<'i>> {
// The stack should be short, so let's simply do linear search and duplicate.
if state.aliases_expanding.contains(&id) {
return Err(TemplateParseError::with_span(
TemplateParseErrorKind::RecursiveAlias(id.to_string()),
span,
));
}
let mut aliases_expanding = state.aliases_expanding.to_vec();
aliases_expanding.push(id);
let expanding_state = State {
aliases_map: state.aliases_map,
aliases_expanding: &aliases_expanding,
locals,
};
// Parsed defn could be cached if needed.
parse_template(defn)
.and_then(|node| expand_node(node, expanding_state))
.map(|node| {
ExpressionNode::new(ExpressionKind::AliasExpanded(id, Box::new(node)), span)
})
.map_err(|e| e.within_alias_expansion(id, span))
}
fn expand_list<'i>(
nodes: Vec<ExpressionNode<'i>>,
state: State<'_, 'i>,
) -> TemplateParseResult<Vec<ExpressionNode<'i>>> {
nodes
.into_iter()
.map(|node| expand_node(node, state))
.try_collect()
}
fn expand_function_call<'i>(
function: FunctionCallNode<'i>,
state: State<'_, 'i>,
) -> TemplateParseResult<FunctionCallNode<'i>> {
Ok(FunctionCallNode {
name: function.name,
name_span: function.name_span,
args: expand_list(function.args, state)?,
args_span: function.args_span,
})
}
fn expand_node<'i>(
mut node: ExpressionNode<'i>,
state: State<'_, 'i>,
) -> TemplateParseResult<ExpressionNode<'i>> {
match node.kind {
ExpressionKind::Identifier(name) => {
if let Some(node) = state.locals.get(name) {
Ok(node.clone())
} else if let Some((id, defn)) = state.aliases_map.get_symbol(name) {
let locals = HashMap::new(); // Don't spill out the current scope
expand_defn(id, defn, &locals, node.span, state)
} else {
Ok(node)
}
}
ExpressionKind::Boolean(_) | ExpressionKind::Integer(_) | ExpressionKind::String(_) => {
Ok(node)
}
ExpressionKind::Unary(op, arg) => {
let arg = Box::new(expand_node(*arg, state)?);
node.kind = ExpressionKind::Unary(op, arg);
Ok(node)
}
ExpressionKind::Binary(op, lhs, rhs) => {
let lhs = Box::new(expand_node(*lhs, state)?);
let rhs = Box::new(expand_node(*rhs, state)?);
node.kind = ExpressionKind::Binary(op, lhs, rhs);
Ok(node)
}
ExpressionKind::Concat(nodes) => {
node.kind = ExpressionKind::Concat(expand_list(nodes, state)?);
Ok(node)
}
ExpressionKind::FunctionCall(function) => {
if let Some((id, params, defn)) = state.aliases_map.get_function(function.name) {
if function.args.len() != params.len() {
return Err(TemplateParseError::invalid_arguments(
&function,
format!("Expected {} arguments", params.len()),
));
}
// Resolve arguments in the current scope, and pass them in to the alias
// expansion scope.
let args = expand_list(function.args, state)?;
let locals = params.iter().map(|s| s.as_str()).zip(args).collect();
expand_defn(id, defn, &locals, node.span, state)
} else {
node.kind =
ExpressionKind::FunctionCall(expand_function_call(function, state)?);
Ok(node)
}
}
ExpressionKind::MethodCall(method) => {
node.kind = ExpressionKind::MethodCall(MethodCallNode {
object: Box::new(expand_node(*method.object, state)?),
function: expand_function_call(method.function, state)?,
});
Ok(node)
}
ExpressionKind::Lambda(lambda) => {
node.kind = ExpressionKind::Lambda(LambdaNode {
params: lambda.params,
params_span: lambda.params_span,
body: Box::new(expand_node(*lambda.body, state)?),
});
Ok(node)
}
ExpressionKind::AliasExpanded(id, subst) => {
// Just in case the original tree contained AliasExpanded node.
let subst = Box::new(expand_node(*subst, state)?);
node.kind = ExpressionKind::AliasExpanded(id, subst);
Ok(node)
}
}
}
let state = State {
aliases_map,
aliases_expanding: &[],
locals: &HashMap::new(),
};
expand_node(node, state)
}
/// Parses text into AST nodes, and expands aliases.
///
/// No type/name checking is made at this stage.
pub fn parse<'i>(
template_text: &'i str,
aliases_map: &'i TemplateAliasesMap,
) -> TemplateParseResult<ExpressionNode<'i>> {
let node = parse_template(template_text)?;
expand_aliases(node, aliases_map)
}
pub fn expect_no_arguments(function: &FunctionCallNode) -> TemplateParseResult<()> {
if function.args.is_empty() {
Ok(())
} else {
Err(TemplateParseError::invalid_arguments(
function,
"Expected 0 arguments",
))
}
}
/// Extracts exactly N required arguments.
pub fn expect_exact_arguments<'a, 'i, const N: usize>(
function: &'a FunctionCallNode<'i>,
) -> TemplateParseResult<&'a [ExpressionNode<'i>; N]> {
function.args.as_slice().try_into().map_err(|_| {
TemplateParseError::invalid_arguments(function, format!("Expected {N} arguments"))
})
}
/// Extracts N required arguments and remainders.
pub fn expect_some_arguments<'a, 'i, const N: usize>(
function: &'a FunctionCallNode<'i>,
) -> TemplateParseResult<(&'a [ExpressionNode<'i>; N], &'a [ExpressionNode<'i>])> {
if function.args.len() >= N {
let (required, rest) = function.args.split_at(N);
Ok((required.try_into().unwrap(), rest))
} else {
Err(TemplateParseError::invalid_arguments(
function,
format!("Expected at least {N} arguments"),
))
}
}
/// Extracts N required arguments and M optional arguments.
pub fn expect_arguments<'a, 'i, const N: usize, const M: usize>(
function: &'a FunctionCallNode<'i>,
) -> TemplateParseResult<(
&'a [ExpressionNode<'i>; N],
[Option<&'a ExpressionNode<'i>>; M],
)> {
let count_range = N..=(N + M);
if count_range.contains(&function.args.len()) {
let (required, rest) = function.args.split_at(N);
let mut optional = rest.iter().map(Some).collect_vec();
optional.resize(M, None);
Ok((required.try_into().unwrap(), optional.try_into().unwrap()))
} else {
Err(TemplateParseError::invalid_arguments(
function,
format!("Expected {min} to {max} arguments", min = N, max = N + M),
))
}
}
/// Applies the given function if the `node` is a string literal.
pub fn expect_string_literal_with<'a, 'i, T>(
node: &'a ExpressionNode<'i>,
f: impl FnOnce(&'a str, pest::Span<'i>) -> TemplateParseResult<T>,
) -> TemplateParseResult<T> {
match &node.kind {
ExpressionKind::String(s) => f(s, node.span),
ExpressionKind::Identifier(_)
| ExpressionKind::Boolean(_)
| ExpressionKind::Integer(_)
| ExpressionKind::Unary(..)
| ExpressionKind::Binary(..)
| ExpressionKind::Concat(_)
| ExpressionKind::FunctionCall(_)
| ExpressionKind::MethodCall(_)
| ExpressionKind::Lambda(_) => Err(TemplateParseError::expression(
"Expected string literal",
node.span,
)),
ExpressionKind::AliasExpanded(id, subst) => expect_string_literal_with(subst, f)
.map_err(|e| e.within_alias_expansion(*id, node.span)),
}
}
/// Applies the given function if the `node` is a lambda.
pub fn expect_lambda_with<'a, 'i, T>(
node: &'a ExpressionNode<'i>,
f: impl FnOnce(&'a LambdaNode<'i>, pest::Span<'i>) -> TemplateParseResult<T>,
) -> TemplateParseResult<T> {
match &node.kind {
ExpressionKind::Lambda(lambda) => f(lambda, node.span),
ExpressionKind::Identifier(_)
| ExpressionKind::Boolean(_)
| ExpressionKind::Integer(_)
| ExpressionKind::String(_)
| ExpressionKind::Unary(..)
| ExpressionKind::Binary(..)
| ExpressionKind::Concat(_)
| ExpressionKind::FunctionCall(_)
| ExpressionKind::MethodCall(_) => Err(TemplateParseError::expression(
"Expected lambda expression",
node.span,
)),
ExpressionKind::AliasExpanded(id, subst) => {
expect_lambda_with(subst, f).map_err(|e| e.within_alias_expansion(*id, node.span))
}
}
}
/// Looks up `table` by the given function name.
pub fn lookup_function<'a, V>(
table: &'a HashMap<&str, V>,
function: &FunctionCallNode,
) -> TemplateParseResult<&'a V> {
if let Some(value) = table.get(function.name) {
Ok(value)
} else {
let candidates = collect_similar(function.name, table.keys());
Err(TemplateParseError::with_span(
TemplateParseErrorKind::NoSuchFunction {
name: function.name.to_owned(),
candidates,
},
function.name_span,
))
}
}
/// Looks up `table` by the given method name.
pub fn lookup_method<'a, V>(
type_name: impl Into<String>,
table: &'a HashMap<&str, V>,
function: &FunctionCallNode,
) -> TemplateParseResult<&'a V> {
if let Some(value) = table.get(function.name) {
Ok(value)
} else {
let candidates = collect_similar(function.name, table.keys());
Err(TemplateParseError::with_span(
TemplateParseErrorKind::NoSuchMethod {
type_name: type_name.into(),
name: function.name.to_owned(),
candidates,
},
function.name_span,
))
}
}
#[cfg(test)]
mod tests {
use assert_matches::assert_matches;
use super::*;
#[derive(Debug)]
struct WithTemplateAliasesMap(TemplateAliasesMap);
impl WithTemplateAliasesMap {
fn parse<'i>(&'i self, template_text: &'i str) -> TemplateParseResult<ExpressionNode<'i>> {
parse(template_text, &self.0)
}
fn parse_normalized<'i>(
&'i self,
template_text: &'i str,
) -> TemplateParseResult<ExpressionNode<'i>> {
self.parse(template_text).map(normalize_tree)
}
}
fn with_aliases(
aliases: impl IntoIterator<Item = (impl AsRef<str>, impl Into<String>)>,
) -> WithTemplateAliasesMap {
let mut aliases_map = TemplateAliasesMap::new();
for (decl, defn) in aliases {
aliases_map.insert(decl, defn).unwrap();
}
WithTemplateAliasesMap(aliases_map)
}
fn parse_into_kind(template_text: &str) -> Result<ExpressionKind, TemplateParseErrorKind> {
parse_template(template_text)
.map(|node| node.kind)
.map_err(|err| err.kind)
}
fn parse_normalized(template_text: &str) -> TemplateParseResult<ExpressionNode> {
parse_template(template_text).map(normalize_tree)
}
/// Drops auxiliary data of AST so it can be compared with other node.
fn normalize_tree(node: ExpressionNode) -> ExpressionNode {
fn empty_span() -> pest::Span<'static> {
pest::Span::new("", 0, 0).unwrap()
}
fn normalize_list(nodes: Vec<ExpressionNode>) -> Vec<ExpressionNode> {
nodes.into_iter().map(normalize_tree).collect()
}
fn normalize_function_call(function: FunctionCallNode) -> FunctionCallNode {
FunctionCallNode {
name: function.name,
name_span: empty_span(),
args: normalize_list(function.args),
args_span: empty_span(),
}
}
let normalized_kind = match node.kind {
ExpressionKind::Identifier(_)
| ExpressionKind::Boolean(_)
| ExpressionKind::Integer(_)
| ExpressionKind::String(_) => node.kind,
ExpressionKind::Unary(op, arg) => {
let arg = Box::new(normalize_tree(*arg));
ExpressionKind::Unary(op, arg)
}
ExpressionKind::Binary(op, lhs, rhs) => {
let lhs = Box::new(normalize_tree(*lhs));
let rhs = Box::new(normalize_tree(*rhs));
ExpressionKind::Binary(op, lhs, rhs)
}
ExpressionKind::Concat(nodes) => ExpressionKind::Concat(normalize_list(nodes)),
ExpressionKind::FunctionCall(function) => {
ExpressionKind::FunctionCall(normalize_function_call(function))
}
ExpressionKind::MethodCall(method) => {
let object = Box::new(normalize_tree(*method.object));
let function = normalize_function_call(method.function);
ExpressionKind::MethodCall(MethodCallNode { object, function })
}
ExpressionKind::Lambda(lambda) => {
let body = Box::new(normalize_tree(*lambda.body));
ExpressionKind::Lambda(LambdaNode {
params: lambda.params,
params_span: empty_span(),
body,
})
}
ExpressionKind::AliasExpanded(_, subst) => normalize_tree(*subst).kind,
};
ExpressionNode {
kind: normalized_kind,
span: empty_span(),
}
}
#[test]
fn test_parse_tree_eq() {
assert_eq!(
normalize_tree(parse_template(r#" commit_id.short(1 ) ++ description"#).unwrap()),
normalize_tree(parse_template(r#"commit_id.short( 1 )++(description)"#).unwrap()),
);
assert_ne!(
normalize_tree(parse_template(r#" "ab" "#).unwrap()),
normalize_tree(parse_template(r#" "a" ++ "b" "#).unwrap()),
);
assert_ne!(
normalize_tree(parse_template(r#" "foo" ++ "0" "#).unwrap()),
normalize_tree(parse_template(r#" "foo" ++ 0 "#).unwrap()),
);
}
#[test]
fn test_parse_whitespace() {
let ascii_whitespaces: String = ('\x00'..='\x7f')
.filter(char::is_ascii_whitespace)
.collect();
assert_eq!(
parse_normalized(&format!("{ascii_whitespaces}f()")).unwrap(),
parse_normalized("f()").unwrap(),
);
}
#[test]
fn test_parse_operator_syntax() {
// Operator precedence
assert_eq!(
parse_normalized("!!x").unwrap(),
parse_normalized("!(!x)").unwrap(),
);
assert_eq!(
parse_normalized("!x.f() || !g()").unwrap(),
parse_normalized("(!(x.f())) || (!(g()))").unwrap(),
);
assert_eq!(
parse_normalized("x.f() || y || z").unwrap(),
parse_normalized("((x.f()) || y) || z").unwrap(),
);
assert_eq!(
parse_normalized("x || y && z.h()").unwrap(),
parse_normalized("x || (y && (z.h()))").unwrap(),
);
// Logical operator bounds more tightly than concatenation. This might
// not be so intuitive, but should be harmless.
assert_eq!(
parse_normalized(r"x && y ++ z").unwrap(),
parse_normalized(r"(x && y) ++ z").unwrap(),
);
assert_eq!(
parse_normalized(r"x ++ y || z").unwrap(),
parse_normalized(r"x ++ (y || z)").unwrap(),
);
// Expression span
assert_eq!(parse_template(" ! x ").unwrap().span.as_str(), "! x");
assert_eq!(parse_template(" x ||y ").unwrap().span.as_str(), "x ||y");
}
#[test]
fn test_function_call_syntax() {
// Trailing comma isn't allowed for empty argument
assert!(parse_template(r#" "".first_line() "#).is_ok());
assert!(parse_template(r#" "".first_line(,) "#).is_err());
// Trailing comma is allowed for the last argument
assert!(parse_template(r#" "".contains("") "#).is_ok());
assert!(parse_template(r#" "".contains("",) "#).is_ok());
assert!(parse_template(r#" "".contains("" , ) "#).is_ok());
assert!(parse_template(r#" "".contains(,"") "#).is_err());
assert!(parse_template(r#" "".contains("",,) "#).is_err());
assert!(parse_template(r#" "".contains("" , , ) "#).is_err());
assert!(parse_template(r#" label("","") "#).is_ok());
assert!(parse_template(r#" label("","",) "#).is_ok());
assert!(parse_template(r#" label("",,"") "#).is_err());
// Boolean literal cannot be used as a function name
assert!(parse_template("false()").is_err());
// Function arguments can be any expression
assert!(parse_template("f(false)").is_ok());
}
#[test]
fn test_method_call_syntax() {
assert_eq!(
parse_normalized("x.f().g()").unwrap(),
parse_normalized("(x.f()).g()").unwrap(),
);
// Expression span
assert_eq!(parse_template(" x.f() ").unwrap().span.as_str(), "x.f()");
assert_eq!(
parse_template(" x.f().g() ").unwrap().span.as_str(),
"x.f().g()",
);
}
#[test]
fn test_lambda_syntax() {
fn unwrap_lambda(node: ExpressionNode<'_>) -> LambdaNode<'_> {
match node.kind {
ExpressionKind::Lambda(lambda) => lambda,
_ => panic!("unexpected expression: {node:?}"),
}
}
let lambda = unwrap_lambda(parse_template("|| a").unwrap());
assert_eq!(lambda.params.len(), 0);
assert_eq!(lambda.body.kind, ExpressionKind::Identifier("a"));
let lambda = unwrap_lambda(parse_template("|foo| a").unwrap());
assert_eq!(lambda.params.len(), 1);
let lambda = unwrap_lambda(parse_template("|foo, b| a").unwrap());
assert_eq!(lambda.params.len(), 2);
// No body
assert!(parse_template("||").is_err());
// Binding
assert_eq!(
parse_normalized("|| x ++ y").unwrap(),
parse_normalized("|| (x ++ y)").unwrap(),
);
assert_eq!(
parse_normalized("f( || x, || y)").unwrap(),
parse_normalized("f((|| x), (|| y))").unwrap(),
);
assert_eq!(
parse_normalized("|| x ++ || y").unwrap(),
parse_normalized("|| (x ++ (|| y))").unwrap(),
);
// Lambda vs logical operator: weird, but this is type error anyway
assert_eq!(
parse_normalized("x||||y").unwrap(),
parse_normalized("x || (|| y)").unwrap(),
);
assert_eq!(
parse_normalized("||||x").unwrap(),
parse_normalized("|| (|| x)").unwrap(),
);
// Trailing comma
assert!(parse_template("|,| a").is_err());
assert!(parse_template("|x,| a").is_ok());
assert!(parse_template("|x , | a").is_ok());
assert!(parse_template("|,x| a").is_err());
assert!(parse_template("| x,y,| a").is_ok());
assert!(parse_template("|x,,y| a").is_err());
// Formal parameter can't be redefined
assert_eq!(
parse_template("|x, x| a").unwrap_err().kind,
TemplateParseErrorKind::RedefinedFunctionParameter
);
// Boolean literal cannot be used as a parameter name
assert!(parse_template("|false| a").is_err());
}
#[test]
fn test_keyword_literal() {
assert_eq!(parse_into_kind("false"), Ok(ExpressionKind::Boolean(false)));
assert_eq!(parse_into_kind("(true)"), Ok(ExpressionKind::Boolean(true)));
// Keyword literals are case sensitive
assert_eq!(
parse_into_kind("False"),
Ok(ExpressionKind::Identifier("False")),
);
assert_eq!(
parse_into_kind("tRue"),
Ok(ExpressionKind::Identifier("tRue")),
);
}
#[test]
fn test_string_literal() {
// "\<char>" escapes
assert_eq!(
parse_into_kind(r#" "\t\r\n\"\\\0" "#),
Ok(ExpressionKind::String("\t\r\n\"\\\0".to_owned())),
);
// Invalid "\<char>" escape
assert_eq!(
parse_into_kind(r#" "\y" "#),
Err(TemplateParseErrorKind::SyntaxError),
);
// Single-quoted raw string
assert_eq!(
parse_into_kind(r#" '' "#),
Ok(ExpressionKind::String("".to_owned())),
);
assert_eq!(
parse_into_kind(r#" 'a\n' "#),
Ok(ExpressionKind::String(r"a\n".to_owned())),
);
assert_eq!(
parse_into_kind(r#" '\' "#),
Ok(ExpressionKind::String(r"\".to_owned())),
);
assert_eq!(
parse_into_kind(r#" '"' "#),
Ok(ExpressionKind::String(r#"""#.to_owned())),
);
}
#[test]
fn test_integer_literal() {
assert_eq!(parse_into_kind("0"), Ok(ExpressionKind::Integer(0)));
assert_eq!(parse_into_kind("(42)"), Ok(ExpressionKind::Integer(42)));
assert_eq!(
parse_into_kind("00"),
Err(TemplateParseErrorKind::SyntaxError),
);
assert_eq!(
parse_into_kind(&format!("{}", i64::MAX)),
Ok(ExpressionKind::Integer(i64::MAX)),
);
assert_matches!(
parse_into_kind(&format!("{}", (i64::MAX as u64) + 1)),
Err(TemplateParseErrorKind::Expression(_))
);
}
#[test]
fn test_parse_alias_decl() {
let mut aliases_map = TemplateAliasesMap::new();
aliases_map.insert("sym", r#""is symbol""#).unwrap();
aliases_map.insert("func(a)", r#""is function""#).unwrap();
let (id, defn) = aliases_map.get_symbol("sym").unwrap();
assert_eq!(id, TemplateAliasId::Symbol("sym"));
assert_eq!(defn, r#""is symbol""#);
let (id, params, defn) = aliases_map.get_function("func").unwrap();
assert_eq!(id, TemplateAliasId::Function("func"));
assert_eq!(params, ["a"]);
assert_eq!(defn, r#""is function""#);
// Formal parameter 'a' can't be redefined
assert_eq!(
aliases_map.insert("f(a, a)", r#""""#).unwrap_err().kind,
TemplateParseErrorKind::RedefinedFunctionParameter
);
// Boolean literal cannot be used as a symbol, function, or parameter name
assert!(aliases_map.insert("false", r#"""#).is_err());
assert!(aliases_map.insert("true()", r#"""#).is_err());
assert!(aliases_map.insert("f(false)", r#"""#).is_err());
// Trailing comma isn't allowed for empty parameter
assert!(aliases_map.insert("f(,)", r#"""#).is_err());
// Trailing comma is allowed for the last parameter
assert!(aliases_map.insert("g(a,)", r#"""#).is_ok());
assert!(aliases_map.insert("h(a , )", r#"""#).is_ok());
assert!(aliases_map.insert("i(,a)", r#"""#).is_err());
assert!(aliases_map.insert("j(a,,)", r#"""#).is_err());
assert!(aliases_map.insert("k(a , , )", r#"""#).is_err());
assert!(aliases_map.insert("l(a,b,)", r#"""#).is_ok());
assert!(aliases_map.insert("m(a,,b)", r#"""#).is_err());
}
#[test]
fn test_expand_symbol_alias() {
assert_eq!(
with_aliases([("AB", "a ++ b")])
.parse_normalized("AB ++ c")
.unwrap(),
parse_normalized("(a ++ b) ++ c").unwrap(),
);
assert_eq!(
with_aliases([("AB", "a ++ b")])
.parse_normalized("if(AB, label(c, AB))")
.unwrap(),
parse_normalized("if((a ++ b), label(c, (a ++ b)))").unwrap(),
);
// Multi-level substitution.
assert_eq!(
with_aliases([("A", "BC"), ("BC", "b ++ C"), ("C", "c")])
.parse_normalized("A")
.unwrap(),
parse_normalized("b ++ c").unwrap(),
);
// Operator expression can be expanded in concatenation.
assert_eq!(
with_aliases([("AB", "a || b")])
.parse_normalized("AB ++ c")
.unwrap(),
parse_normalized("(a || b) ++ c").unwrap(),
);
// Operands should be expanded.
assert_eq!(
with_aliases([("A", "a"), ("B", "b")])
.parse_normalized("A || !B")
.unwrap(),
parse_normalized("a || !b").unwrap(),
);
// Method receiver and arguments should be expanded.
assert_eq!(
with_aliases([("A", "a")])
.parse_normalized("A.f()")
.unwrap(),
parse_normalized("a.f()").unwrap(),
);
assert_eq!(
with_aliases([("A", "a"), ("B", "b")])
.parse_normalized("x.f(A, B)")
.unwrap(),
parse_normalized("x.f(a, b)").unwrap(),
);
// Lambda expression body should be expanded.
assert_eq!(
with_aliases([("A", "a")]).parse_normalized("|| A").unwrap(),
parse_normalized("|| a").unwrap(),
);
// No matter if 'A' is a formal parameter. Alias substitution isn't scoped.
// If we don't like this behavior, maybe we can turn off alias substitution
// for lambda parameters.
assert_eq!(
with_aliases([("A", "a ++ b")])
.parse_normalized("|A| A")
.unwrap(),
parse_normalized("|A| (a ++ b)").unwrap(),
);
// Infinite recursion, where the top-level error isn't of RecursiveAlias kind.
assert_eq!(
with_aliases([("A", "A")]).parse("A").unwrap_err().kind,
TemplateParseErrorKind::BadAliasExpansion("A".to_owned()),
);
assert_eq!(
with_aliases([("A", "B"), ("B", "b ++ C"), ("C", "c ++ B")])
.parse("A")
.unwrap_err()
.kind,
TemplateParseErrorKind::BadAliasExpansion("A".to_owned()),
);
// Error in alias definition.
assert_eq!(
with_aliases([("A", "a(")]).parse("A").unwrap_err().kind,
TemplateParseErrorKind::BadAliasExpansion("A".to_owned()),
);
}
#[test]
fn test_expand_function_alias() {
assert_eq!(
with_aliases([("F( )", "a")])
.parse_normalized("F()")
.unwrap(),
parse_normalized("a").unwrap(),
);
assert_eq!(
with_aliases([("F( x )", "x")])
.parse_normalized("F(a)")
.unwrap(),
parse_normalized("a").unwrap(),
);
assert_eq!(
with_aliases([("F( x, y )", "x ++ y")])
.parse_normalized("F(a, b)")
.unwrap(),
parse_normalized("a ++ b").unwrap(),
);
// Arguments should be resolved in the current scope.
assert_eq!(
with_aliases([("F(x,y)", "if(x, y)")])
.parse_normalized("F(a ++ y, b ++ x)")
.unwrap(),
parse_normalized("if((a ++ y), (b ++ x))").unwrap(),
);
// F(a) -> if(G(a), y) -> if((x ++ a), y)
assert_eq!(
with_aliases([("F(x)", "if(G(x), y)"), ("G(y)", "x ++ y")])
.parse_normalized("F(a)")
.unwrap(),
parse_normalized("if((x ++ a), y)").unwrap(),
);
// F(G(a)) -> F(x ++ a) -> if(G(x ++ a), y) -> if((x ++ (x ++ a)), y)
assert_eq!(
with_aliases([("F(x)", "if(G(x), y)"), ("G(y)", "x ++ y")])
.parse_normalized("F(G(a))")
.unwrap(),
parse_normalized("if((x ++ (x ++ a)), y)").unwrap(),
);
// Function parameter should precede the symbol alias.
assert_eq!(
with_aliases([("F(X)", "X"), ("X", "x")])
.parse_normalized("F(a) ++ X")
.unwrap(),
parse_normalized("a ++ x").unwrap(),
);
// Function parameter shouldn't be expanded in symbol alias.
assert_eq!(
with_aliases([("F(x)", "x ++ A"), ("A", "x")])
.parse_normalized("F(a)")
.unwrap(),
parse_normalized("a ++ x").unwrap(),
);
// Function and symbol aliases reside in separate namespaces.
assert_eq!(
with_aliases([("A()", "A"), ("A", "a")])
.parse_normalized("A()")
.unwrap(),
parse_normalized("a").unwrap(),
);
// Method call shouldn't be substituted by function alias.
assert_eq!(
with_aliases([("F()", "f()")])
.parse_normalized("x.F()")
.unwrap(),
parse_normalized("x.F()").unwrap(),
);
// Formal parameter shouldn't be substituted by alias parameter, but
// the expression should be substituted.
assert_eq!(
with_aliases([("F(x)", "|x| x")])
.parse_normalized("F(a ++ b)")
.unwrap(),
parse_normalized("|x| (a ++ b)").unwrap(),
);
// Invalid number of arguments.
assert_matches!(
with_aliases([("F()", "x")]).parse("F(a)").unwrap_err().kind,
TemplateParseErrorKind::InvalidArguments { .. }
);
assert_matches!(
with_aliases([("F(x)", "x")]).parse("F()").unwrap_err().kind,
TemplateParseErrorKind::InvalidArguments { .. }
);
assert_matches!(
with_aliases([("F(x,y)", "x ++ y")])
.parse("F(a,b,c)")
.unwrap_err()
.kind,
TemplateParseErrorKind::InvalidArguments { .. }
);
// Infinite recursion, where the top-level error isn't of RecursiveAlias kind.
assert_eq!(
with_aliases([("F(x)", "G(x)"), ("G(x)", "H(x)"), ("H(x)", "F(x)")])
.parse("F(a)")
.unwrap_err()
.kind,
TemplateParseErrorKind::BadAliasExpansion("F()".to_owned()),
);
}
}
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