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Add repeatMatch functions to DSL #161

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Merged
merged 4 commits into from
Feb 16, 2022
Merged

Add repeatMatch functions to DSL #161

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1d62a14
Add `repeating` functions to DSL
natecook1000 Feb 14, 2022
919d8df
Rename to repeatMatch(...) / repeatMatch(count:)
natecook1000 Feb 14, 2022
8d8d5b7
Address feedback
natecook1000 Feb 16, 2022
b408020
Merge branch 'main' into repeating
natecook1000 Feb 16, 2022
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130 changes: 99 additions & 31 deletions Sources/VariadicsGenerator/VariadicsGenerator.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -151,6 +151,8 @@ struct VariadicsGenerator: ParsableCommand {
print("\(kind.rawValue) ", terminator: "", to: &standardError)
emitQuantifier(kind: kind, arity: arity)
}
print("repeating ", terminator: "", to: &standardError)
emitRepeating(arity: arity)
print(to: &standardError)
}

Expand Down Expand Up @@ -307,69 +309,135 @@ struct VariadicsGenerator: ParsableCommand {
}
}
}

struct QuantifierParameters {
var genericParams: String
var captures: String
var capturesTupled: String
var whereClause: String
var quantifiedCaptures: String
var matchType: String

var repeatingWhereClause: String {
whereClause.isEmpty
? "where R.Bound == Int"
: whereClause + ", R.Bound == Int"
}

init(kind: QuantifierKind, arity: Int) {
self.genericParams = {
var result = ""
if arity > 0 {
result += "W"
result += (0..<arity).map { ", C\($0)" }.joined()
result += ", "
}
result += "Component: \(regexProtocolName)"
return result
}()
self.captures = (0..<arity).map { "C\($0)" }.joined(separator: ", ")
self.capturesTupled = arity == 1 ? captures : "(\(captures))"
self.whereClause = arity == 0 ? "" :
"where Component.Match == (W, \(captures))"
self.quantifiedCaptures = kind == .zeroOrOne
? "\(capturesTupled)?"
: "[\(capturesTupled)]"
self.matchType = arity == 0
? baseMatchTypeName
: "(\(baseMatchTypeName), \(quantifiedCaptures))"
}
}

func emitQuantifier(kind: QuantifierKind, arity: Int) {
assert(arity >= 0)
let genericParams: String = {
var result = ""
if arity > 0 {
result += "W"
result += (0..<arity).map { ", C\($0)" }.joined()
result += ", "
}
result += "Component: \(regexProtocolName)"
return result
}()
let captures = (0..<arity).map { "C\($0)" }.joined(separator: ", ")
let capturesTupled = arity == 1 ? captures : "(\(captures))"
let whereClause: String = arity == 0 ? "" :
"where Component.Match == (W, \(captures))"
let quantifiedCaptures: String = {
switch kind {
case .zeroOrOne:
return "\(capturesTupled)?"
case .zeroOrMore, .oneOrMore:
return "[\(capturesTupled)]"
}
}()
let matchType = arity == 0 ? baseMatchTypeName : "(\(baseMatchTypeName), \(quantifiedCaptures))"
let params = QuantifierParameters(kind: kind, arity: arity)
output("""
\(arity == 0 ? "@_disfavoredOverload" : "")
public func \(kind.rawValue)<\(genericParams)>(
public func \(kind.rawValue)<\(params.genericParams)>(
_ component: Component,
_ behavior: QuantificationBehavior = .eagerly
) -> \(regexTypeName)<\(matchType)> \(whereClause) {
) -> \(regexTypeName)<\(params.matchType)> \(params.whereClause) {
.init(node: .quantification(.\(kind.astQuantifierAmount), behavior.astKind, component.regex.root))
}

\(arity == 0 ? "@_disfavoredOverload" : "")
public func \(kind.rawValue)<\(genericParams)>(
public func \(kind.rawValue)<\(params.genericParams)>(
_ behavior: QuantificationBehavior = .eagerly,
@RegexBuilder _ component: () -> Component
) -> \(regexTypeName)<\(matchType)> \(whereClause) {
) -> \(regexTypeName)<\(params.matchType)> \(params.whereClause) {
.init(node: .quantification(.\(kind.astQuantifierAmount), behavior.astKind, component().regex.root))
}

\(arity == 0 ? "@_disfavoredOverload" : "")
public postfix func \(kind.operatorName)<\(genericParams)>(
public postfix func \(kind.operatorName)<\(params.genericParams)>(
_ component: Component
) -> \(regexTypeName)<\(matchType)> \(whereClause) {
) -> \(regexTypeName)<\(params.matchType)> \(params.whereClause) {
.init(node: .quantification(.\(kind.astQuantifierAmount), .eager, component.regex.root))
}

\(kind == .zeroOrOne ?
"""
extension RegexBuilder {
public static func buildLimitedAvailability<\(genericParams)>(
public static func buildLimitedAvailability<\(params.genericParams)>(
_ component: Component
) -> \(regexTypeName)<\(matchType)> \(whereClause) {
) -> \(regexTypeName)<\(params.matchType)> \(params.whereClause) {
.init(node: .quantification(.\(kind.astQuantifierAmount), .eager, component.regex.root))
}
}
""" : "")

""")
}

func emitRepeating(arity: Int) {
assert(arity >= 0)
// `repeatMatch(..<5)` has the same generic semantics as zeroOrMore
let rangeParams = QuantifierParameters(kind: .zeroOrMore, arity: arity)
// `repeatMatch(count:)` has the same generic semantics as oneOrMore
let exactlyParams = QuantifierParameters(kind: .zeroOrMore, arity: arity)
output("""
\(arity == 0 ? "@_disfavoredOverload" : "")
public func repeatMatch<\(exactlyParams.genericParams)>(
_ component: Component,
count: Int
) -> \(regexTypeName)<\(exactlyParams.matchType)> \(exactlyParams.whereClause) {
assert(count > 0, "Must specify a positive count")
// TODO: Emit a warning about `repeatMatch(count: 0)` or `repeatMatch(count: 1)`
return Regex(node: .quantification(.exactly(.init(faking: count)), .eager, component.regex.root))
}

\(arity == 0 ? "@_disfavoredOverload" : "")
public func repeatMatch<\(exactlyParams.genericParams)>(
count: Int,
@RegexBuilder _ component: () -> Component
) -> \(regexTypeName)<\(exactlyParams.matchType)> \(exactlyParams.whereClause) {
assert(count > 0, "Must specify a positive count")
// TODO: Emit a warning about `repeatMatch(count: 0)` or `repeatMatch(count: 1)`
return Regex(node: .quantification(.exactly(.init(faking: count)), .eager, component().regex.root))
}

\(arity == 0 ? "@_disfavoredOverload" : "")
public func repeatMatch<\(rangeParams.genericParams), R: RangeExpression>(
_ component: Component,
_ expression: R,
_ behavior: QuantificationBehavior = .eagerly
) -> \(regexTypeName)<\(rangeParams.matchType)> \(rangeParams.repeatingWhereClause) {
.init(node:
_repeatingNode(expression.relative(to: 0..<Int.max), behavior, component.regex.root))
}

\(arity == 0 ? "@_disfavoredOverload" : "")
public func repeatMatch<\(rangeParams.genericParams), R: RangeExpression>(
_ expression: R,
_ behavior: QuantificationBehavior = .eagerly,
@RegexBuilder _ component: () -> Component
) -> \(regexTypeName)<\(rangeParams.matchType)> \(rangeParams.repeatingWhereClause) {
.init(node:
_repeatingNode(expression.relative(to: 0..<Int.max), behavior, component().regex.root))
}

""")
}

func emitAlternation(leftArity: Int, rightArity: Int) {
let leftGenParams: String = {
Expand Down
28 changes: 28 additions & 0 deletions Sources/_StringProcessing/RegexDSL/DSL.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,34 @@ postfix operator .?
postfix operator .*
postfix operator .+

/// Generates a DSLTree node for a repeated range of the given DSLTree node.
/// Individual public API functions are in the generated Variadics.swift file.
internal func _repeatingNode(
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Nit: How about a static method DSLTree.Node.repeating(_:_:_:)

_ range: Range<Int>,
_ behavior: QuantificationBehavior,
_ node: DSLTree.Node
) -> DSLTree.Node {
// TODO: Throw these as errors
assert(range.lowerBound >= 0, "Cannot specify a negative lower bound")
assert(!range.isEmpty, "Cannot specify an empty range")

switch (range.lowerBound, range.upperBound) {
case (0, Int.max): // 0...
return .quantification(.zeroOrMore, behavior.astKind, node)
case (1, Int.max): // 1...
return .quantification(.oneOrMore, behavior.astKind, node)
case _ where range.count == 1: // ..<1 or ...0 or any range with count == 1
// Note: `behavior` is ignored in this case
return .quantification(.exactly(.init(faking: range.lowerBound)), .eager, node)
case (0, _): // 0..<n or 0...n or ..<n or ...n
return .quantification(.upToN(.init(faking: range.upperBound)), behavior.astKind, node)
case (_, Int.max): // n...
return .quantification(.nOrMore(.init(faking: range.lowerBound)), behavior.astKind, node)
default: // any other range
return .quantification(.range(.init(faking: range.lowerBound), .init(faking: range.upperBound)), behavior.astKind, node)
}
}

// MARK: Alternation

// TODO: Variadic generics
Expand Down
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