Part 4: Parse queries with rust-peg.
There's an unfortunate conflation here between implementing the query parser in `rust-peg` and moving some validation that now happens at parse time to happen later. The result is that we introduce `ParsedFindQuery` as a less-processed `FindQuery`, and that we only use string errors (which is all `rust-peg` supports) instead of the structured errors in query-parser's errors module. The next commit will address this, on the road to removing the `query-parser` module entirely.
This commit is contained in:
Nick Alexander
parent
a8073056f2
commit
09f1d633b5
4 changed files with 372 additions and 1239 deletions
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@ -1,3 +1,4 @@
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/* -*- comment-start: "//"; -*- */
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/* vim: set filetype=rust.rustpeg */
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// Copyright 2016 Mozilla
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@ -24,6 +25,8 @@ use ordered_float::OrderedFloat;
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use uuid::Uuid;
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use entities::*;
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use query;
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use query::FromValue;
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use symbols::*;
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use types::{SpannedValue, Span, ValueAndSpan};
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@ -155,12 +158,14 @@ pub symbol -> SpannedValue =
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ns:( sns:$(symbol_namespace) namespace_separator { sns })?
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n:$(plain_symbol_name)
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{ SpannedValue::from_symbol(ns, n) }
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/ #expected("symbol")
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pub keyword -> SpannedValue =
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keyword_prefix
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ns:( sns:$(symbol_namespace) namespace_separator { sns })?
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n:$(symbol_name)
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{ SpannedValue::from_keyword(ns, n) }
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/ #expected("keyword")
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pub list -> SpannedValue = "(" __ v:(value)* __ ")"
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{ SpannedValue::List(LinkedList::from_iter(v)) }
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@ -188,6 +193,7 @@ pub value -> ValueAndSpan =
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span: Span::new(start, end)
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}
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}
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/ #expected("value")
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atom -> ValueAndSpan
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= v:value {? if v.is_atom() { Ok(v) } else { Err("expected atom") } }
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@ -199,10 +205,29 @@ comment = #quiet<";" [^\r\n]* [\r\n]?>
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__ = (whitespace / comment)*
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// Transaction entity parser starts here.
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pub op -> OpType
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= ":db/add" { OpType::Add }
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/ ":db/retract" { OpType::Retract }
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raw_keyword -> Keyword =
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keyword_prefix
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ns:( sns:$(symbol_namespace) namespace_separator { sns })?
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n:$(symbol_name) {
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match ns {
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Some(ns) => Keyword::namespaced(ns, n),
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None => Keyword::plain(n),
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}
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}
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/ #expected("keyword")
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raw_forward_keyword -> Keyword
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= v:raw_keyword {? if v.is_forward() { Ok(v) } else { Err("expected :forward or :forward/keyword") } }
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raw_backward_keyword -> Keyword
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= v:raw_keyword {? if v.is_backward() { Ok(v) } else { Err("expected :_backword or :backward/_keyword") } }
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raw_namespaced_keyword -> Keyword
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= keyword_prefix ns:$(symbol_namespace) namespace_separator n:$(symbol_name) { Keyword::namespaced(ns, n) }
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/ #expected("namespaced keyword")
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@ -216,16 +241,20 @@ raw_backward_namespaced_keyword -> Keyword
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entid -> Entid
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= v:( raw_basedinteger / raw_hexinteger / raw_octalinteger / raw_integer ) { Entid::Entid(v) }
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/ v:raw_namespaced_keyword { Entid::Ident(v) }
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/ #expected("entid")
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forward_entid -> Entid
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= v:( raw_basedinteger / raw_hexinteger / raw_octalinteger / raw_integer ) { Entid::Entid(v) }
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/ v:raw_forward_namespaced_keyword { Entid::Ident(v) }
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/ #expected("forward entid")
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backward_entid -> Entid
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= v:raw_backward_namespaced_keyword { Entid::Ident(v.to_reversed()) }
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/ #expected("backward entid")
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lookup_ref -> LookupRef<ValueAndSpan>
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= "(" __ "lookup-ref" __ a:(entid) __ v:(value) __ ")" { LookupRef { a: AttributePlace::Entid(a), v } }
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/ #expected("lookup-ref")
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tx_function -> TxFunction
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= "(" __ n:$(symbol_name) __ ")" { TxFunction { op: PlainSymbol::plain(n) } }
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@ -253,6 +282,210 @@ pub entity -> Entity<ValueAndSpan>
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= __ "[" __ op:(op) __ e:(entity_place) __ a:(forward_entid) __ v:(value_place) __ "]" __ { Entity::AddOrRetract { op, e: e, a: AttributePlace::Entid(a), v: v } }
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/ __ "[" __ op:(op) __ e:(value_place) __ a:(backward_entid) __ v:(entity_place) __ "]" __ { Entity::AddOrRetract { op, e: v, a: AttributePlace::Entid(a), v: e } }
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/ __ map:map_notation __ { Entity::MapNotation(map) }
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/ #expected("entity")
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pub entities -> Vec<Entity<ValueAndSpan>>
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= __ "[" __ es:(entity*) __ "]" __ { es }
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// Query parser starts here.
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//
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// We expect every rule except the `raw_*` rules to eat whitespace
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// (with `__`) at its start and finish. That means that every string
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// pattern (say "[") should be bracketed on either side with either a
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// whitespace-eating rule or an explicit whitespace eating `__`.
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query_function -> query::QueryFunction
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= __ n:$(symbol_name) __ {? query::QueryFunction::from_symbol(&PlainSymbol::plain(n)).ok_or("expected query function") }
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fn_arg -> query::FnArg
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= v:value {? query::FnArg::from_value(&v).ok_or("expected query function argument") }
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/ __ "[" args:fn_arg+ "]" __ { query::FnArg::Vector(args) }
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find_elem -> query::Element
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= __ v:variable __ { query::Element::Variable(v) }
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/ __ "(" __ "the" v:variable ")" __ { query::Element::Corresponding(v) }
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/ __ "(" __ "pull" var:variable "[" patterns:pull_attribute+ "]" __ ")" __ { query::Element::Pull(query::Pull { var, patterns }) }
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/ __ "(" func:query_function args:fn_arg* ")" __ { query::Element::Aggregate(query::Aggregate { func, args }) }
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find_spec -> query::FindSpec
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= f:find_elem "." __ { query::FindSpec::FindScalar(f) }
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/ fs:find_elem+ { query::FindSpec::FindRel(fs) }
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/ __ "[" f:find_elem __ "..." __ "]" __ { query::FindSpec::FindColl(f) }
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/ __ "[" fs:find_elem+ "]" __ { query::FindSpec::FindTuple(fs) }
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pull_attribute -> query::PullAttributeSpec
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= __ "*" __ { query::PullAttributeSpec::Wildcard }
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/ __ k:raw_forward_namespaced_keyword __ alias:(":as" __ alias:raw_forward_keyword __ { alias })? {
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let attribute = query::PullConcreteAttribute::Ident(::std::rc::Rc::new(k));
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let alias = alias.map(|alias| ::std::rc::Rc::new(alias));
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query::PullAttributeSpec::Attribute(
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query::NamedPullAttribute {
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attribute,
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alias: alias,
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})
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}
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limit -> query::Limit
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= __ v:variable __ { query::Limit::Variable(v) }
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/ __ n:(raw_octalinteger / raw_hexinteger / raw_basedinteger / raw_integer) __ {?
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if n > 0 {
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Ok(query::Limit::Fixed(n as u64))
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} else {
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Err("expected positive integer")
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}
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}
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order -> query::Order
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= __ "(" __ "asc" v:variable ")" __ { query::Order(query::Direction::Ascending, v) }
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/ __ "(" __ "desc" v:variable ")" __ { query::Order(query::Direction::Descending, v) }
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/ v:variable { query::Order(query::Direction::Ascending, v) }
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pattern_value_place -> query::PatternValuePlace
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= v:value {? query::PatternValuePlace::from_value(&v).ok_or("expected pattern_value_place") }
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pattern_non_value_place -> query::PatternNonValuePlace
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= v:value {? query::PatternNonValuePlace::from_value(&v).ok_or("expected pattern_non_value_place") }
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pattern -> query::WhereClause
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= __ "["
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src:src_var?
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e:pattern_non_value_place
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a:pattern_non_value_place
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v:pattern_value_place?
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tx:pattern_non_value_place?
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"]" __
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{?
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let v = v.unwrap_or(query::PatternValuePlace::Placeholder);
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let tx = tx.unwrap_or(query::PatternNonValuePlace::Placeholder);
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// Pattern::new takes care of reversal of reversed
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// attributes: [?x :foo/_bar ?y] turns into
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// [?y :foo/bar ?x].
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//
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// This is a bit messy: the inner conversion to a Pattern can
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// fail if the input is something like
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//
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// ```edn
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// [?x :foo/_reversed 23.4]
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// ```
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//
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// because
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//
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// ```edn
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// [23.4 :foo/reversed ?x]
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// ```
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//
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// is nonsense. That leaves us with a nested optional, which we unwrap here.
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query::Pattern::new(src, e, a, v, tx)
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.map(query::WhereClause::Pattern)
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.ok_or("expected pattern")
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}
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// TODO: this shouldn't be checked at parse time.
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rule_vars -> BTreeSet<query::Variable>
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= vs:variable+ {?
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let given = vs.len();
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let set: BTreeSet<query::Variable> = vs.into_iter().collect();
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if given != set.len() {
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Err("expected unique variables")
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} else {
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Ok(set)
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}
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}
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or_pattern_clause -> query::OrWhereClause
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= clause:where_clause { query::OrWhereClause::Clause(clause) }
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or_and_clause -> query::OrWhereClause
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= __ "(" __ "and" clauses:where_clause+ ")" __ { query::OrWhereClause::And(clauses) }
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or_where_clause -> query::OrWhereClause
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= or_pattern_clause
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/ or_and_clause
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or_clause -> query::WhereClause
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= __ "(" __ "or" clauses:or_where_clause+ ")" __ {
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query::WhereClause::OrJoin(query::OrJoin::new(query::UnifyVars::Implicit, clauses))
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}
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or_join_clause -> query::WhereClause
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= __ "(" __ "or-join" __ "[" vars:rule_vars "]" clauses:or_where_clause+ ")" __ {
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query::WhereClause::OrJoin(query::OrJoin::new(query::UnifyVars::Explicit(vars), clauses))
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}
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not_clause -> query::WhereClause
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= __ "(" __ "not" clauses:where_clause+ ")" __ {
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query::WhereClause::NotJoin(query::NotJoin::new(query::UnifyVars::Implicit, clauses))
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}
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not_join_clause -> query::WhereClause
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= __ "(" __ "not-join" __ "[" vars:rule_vars "]" clauses:where_clause+ ")" __ {
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query::WhereClause::NotJoin(query::NotJoin::new(query::UnifyVars::Explicit(vars), clauses))
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}
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type_annotation -> query::WhereClause
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= __ "[" __ "(" __ "type" var:variable __ ty:raw_keyword __ ")" __ "]" __ {
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query::WhereClause::TypeAnnotation(
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query::TypeAnnotation {
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value_type: ty,
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variable: var,
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})
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}
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pred -> query::WhereClause
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= __ "[" __ "(" func:query_function args:fn_arg* ")" __ "]" __ {
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query::WhereClause::Pred(
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query::Predicate {
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operator: func.0,
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args: args,
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})
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}
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pub where_fn -> query::WhereClause
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= __ "[" __ "(" func:query_function args:fn_arg* ")" __ binding:binding "]" __ {
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query::WhereClause::WhereFn(
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query::WhereFn {
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operator: func.0,
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args: args,
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binding,
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})
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}
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where_clause -> query::WhereClause
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// Right now we only support patterns and predicates. See #239 for more.
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= pattern
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/ or_join_clause
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/ or_clause
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/ not_join_clause
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/ not_clause
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/ type_annotation
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/ pred
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/ where_fn
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query_part -> query::QueryPart
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= __ ":find" fs:find_spec { query::QueryPart::FindSpec(fs) }
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/ __ ":in" in_vars:variable+ { query::QueryPart::InVars(in_vars) }
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/ __ ":limit" l:limit { query::QueryPart::Limit(l) }
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/ __ ":order" os:order+ { query::QueryPart::Order(os) }
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/ __ ":where" ws:where_clause+ { query::QueryPart::WhereClauses(ws) }
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/ __ ":with" with_vars:variable+ { query::QueryPart::WithVars(with_vars) }
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pub query -> query::ParsedFindQuery
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= __ "[" qps:query_part+ "]" __ {? query::ParsedFindQuery::from_parts(qps) }
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variable -> query::Variable
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= v:value {? query::Variable::from_value(&v).ok_or("expected variable") }
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src_var -> query::SrcVar
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= v:value {? query::SrcVar::from_value(&v).ok_or("expected src_var") }
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variable_or_placeholder -> query::VariableOrPlaceholder
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= v:variable { query::VariableOrPlaceholder::Variable(v) }
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/ __ "_" __ { query::VariableOrPlaceholder::Placeholder }
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binding -> query::Binding
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= __ "[" __ "[" vs:variable_or_placeholder+ "]" __ "]" __ { query::Binding::BindRel(vs) }
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/ __ "[" v:variable "..." __ "]" __ { query::Binding::BindColl(v) }
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/ __ "[" vs:variable_or_placeholder+ "]" __ { query::Binding::BindTuple(vs) }
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/ v:variable { query::Binding::BindScalar(v) }
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134
edn/src/query.rs
134
edn/src/query.rs
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@ -949,6 +949,15 @@ pub struct NotJoin {
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pub clauses: Vec<WhereClause>,
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}
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impl NotJoin {
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pub fn new(unify_vars: UnifyVars, clauses: Vec<WhereClause>) -> NotJoin {
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NotJoin {
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unify_vars: unify_vars,
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clauses: clauses,
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}
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}
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}
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#[derive(Clone, Debug, Eq, PartialEq)]
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pub struct TypeAnnotation {
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pub value_type: Keyword,
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@ -981,6 +990,131 @@ pub struct FindQuery {
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// TODO: in_rules;
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}
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#[allow(dead_code)]
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#[derive(Debug, Eq, PartialEq)]
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pub struct ParsedFindQuery {
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pub find_spec: FindSpec,
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pub default_source: SrcVar,
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pub with: Vec<Variable>,
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pub in_vars: Vec<Variable>,
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pub in_sources: BTreeSet<SrcVar>,
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pub limit: Limit,
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pub where_clauses: Vec<WhereClause>,
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pub order: Option<Vec<Order>>,
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// TODO: in_rules;
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}
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pub(crate) enum QueryPart {
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FindSpec(FindSpec),
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WithVars(Vec<Variable>),
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InVars(Vec<Variable>),
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Limit(Limit),
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WhereClauses(Vec<WhereClause>),
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Order(Vec<Order>),
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}
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impl ParsedFindQuery {
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pub(crate) fn from_parts(parts: Vec<QueryPart>) -> std::result::Result<ParsedFindQuery, &'static str> {
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let mut find_spec: Option<FindSpec> = None;
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let mut with: Option<Vec<Variable>> = None;
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let mut in_vars: Option<Vec<Variable>> = None;
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let mut limit: Option<Limit> = None;
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let mut where_clauses: Option<Vec<WhereClause>> = None;
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let mut order: Option<Vec<Order>> = None;
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for part in parts.into_iter() {
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match part {
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QueryPart::FindSpec(x) => {
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if find_spec.is_some() {
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return Err("find query has repeated :find");
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}
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find_spec = Some(x)
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},
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QueryPart::WithVars(x) => {
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if with.is_some() {
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return Err("find query has repeated :with");
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}
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with = Some(x)
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},
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QueryPart::InVars(x) => {
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if in_vars.is_some() {
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return Err("find query has repeated :in");
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}
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in_vars = Some(x)
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},
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QueryPart::Limit(x) => {
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if limit.is_some() {
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return Err("find query has repeated :limit");
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}
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limit = Some(x)
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},
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QueryPart::WhereClauses(x) => {
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if where_clauses.is_some() {
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return Err("find query has repeated :where");
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}
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where_clauses = Some(x)
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},
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QueryPart::Order(x) => {
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if order.is_some() {
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return Err("find query has repeated :order");
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}
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order = Some(x)
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},
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}
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}
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Ok(ParsedFindQuery {
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find_spec: find_spec.ok_or("expected :find")?,
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default_source: SrcVar::DefaultSrc,
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with: with.unwrap_or(vec![]),
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in_vars: in_vars.unwrap_or(vec![]),
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in_sources: BTreeSet::default(),
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limit: limit.unwrap_or(Limit::None),
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where_clauses: where_clauses.ok_or("expected :where")?,
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order,
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})
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}
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pub fn into_find_query(self: ParsedFindQuery) -> Result<FindQuery, &'static str> {
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let in_vars = {
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let len = self.in_vars.len();
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let set: BTreeSet<Variable> = self.in_vars.into_iter().collect();
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if len != set.len() {
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return Err("find query has repeated :in variable".into());
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}
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set
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};
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let with = {
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let len = self.with.len();
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let set: BTreeSet<Variable> = self.with.into_iter().collect();
|
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if len != set.len() {
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return Err("find query has repeated :with variable".into());
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}
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set
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};
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// Make sure that if we have `:limit ?x`, `?x` appears in `:in`.
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if let Limit::Variable(ref v) = self.limit {
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if !in_vars.contains(v) {
|
||||
return Err("limit var not present in :in");
|
||||
}
|
||||
}
|
||||
|
||||
Ok(FindQuery {
|
||||
find_spec: self.find_spec,
|
||||
default_source: self.default_source,
|
||||
with,
|
||||
in_vars,
|
||||
in_sources: self.in_sources,
|
||||
limit: self.limit,
|
||||
where_clauses: self.where_clauses,
|
||||
order: self.order,
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
impl FindQuery {
|
||||
pub fn simple(spec: FindSpec, where_clauses: Vec<WhereClause>) -> FindQuery {
|
||||
FindQuery {
|
||||
|
|
|
|||
|
|
@ -22,7 +22,6 @@ extern crate edn;
|
|||
extern crate mentat_parser_utils;
|
||||
|
||||
mod errors;
|
||||
mod parse;
|
||||
|
||||
pub use errors::{
|
||||
Error,
|
||||
|
|
@ -31,6 +30,8 @@ pub use errors::{
|
|||
ResultExt,
|
||||
};
|
||||
|
||||
pub use parse::{
|
||||
parse_find_string,
|
||||
};
|
||||
pub fn parse_find_string(string: &str) -> Result<edn::query::FindQuery> {
|
||||
edn::parse::query(string)
|
||||
.map_err(|e| e.into())
|
||||
.and_then(|parsed| parsed.into_find_query().map_err(|e| e.into()))
|
||||
}
|
||||
|
|
|
|||
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