Syntax.pudu

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1/** @Log.Expressions.Syntax.Tree — the parsed form of filter expressions */2module PuduLangLog.Expressions.Syntax34import PuduLangLog as Log56/** @Log.Expressions.Syntax.Expression — one node of an expression */7export type Expression = Constant(Log.Value)8  | Name(Str)9  | Member(Expression, Str)10  | Index(Expression, Expression)11  | Wildcard(Expression, Quantifier)12  | Call(Str, Array[Expression], Bool)13  | Unary(Str, Expression)14  | Binary(Str, Expression, Expression, Bool)15  | ArrayOf(Array[Element])16  | ObjectOf(Array[Field])17  | Conditional(Expression, Expression, Expression)1819/** @Log.Expressions.Syntax.Quantifier — whether any or every element must match */20export type Quantifier = AnyOf | AllOf2122/** @Log.Expressions.Syntax.Element — an array item or a spread array */23export type Element = Item(Expression) | SpreadItems(Expression)2425/** @Log.Expressions.Syntax.Field — an object member or a spread object */26export type Field = Pair(Str, Expression) | SpreadMembers(Expression)2728/// Every name an expression reads, in order of first appearance, locals included.29export fn namesIn(expression: &Expression) -> Array[Str] {30  var found: Array[Str] = []31  for part in partsOf(expression) {32    if let Name(name) = part {33      if !found.contains(name) { found = found.push(name) }34    }35  }36  found37}3839/// Every function an expression calls, by lower-case name.40export fn callsIn(expression: &Expression) -> Array[Str] {41  var found: Array[Str] = []42  for part in partsOf(expression) {43    if let Call(name, _, _) = part { found = found.push(name) }44  }45  found46}4748/// The expression and every expression inside it, outermost first.49fn partsOf(expression: &Expression) -> Array[Expression] {50  var found = [*expression]51  for child in children(expression) { found = found.concat(partsOf(&child)) }52  found53}5455/// The expressions directly inside an expression.56fn children(expression: &Expression) -> Array[Expression] {57  match expression {58    case Constant(_) => []59    case Name(_) => []60    case Member(target, _) => [target]61    case Index(target, key) => [target, key]62    case Wildcard(target, _) => [target]63    case Call(_, arguments, _) => arguments64    case Unary(_, operand) => [operand]65    case Binary(_, left, right, _) => [left, right]66    case ArrayOf(elements) => elements.map(|element: Element| match element {67        case Item(item) => item68        case SpreadItems(items) => items69      })70    case ObjectOf(fields) => fields.map(|field: Field| match field {71        case Pair(_, held) => held72        case SpreadMembers(members) => members73      })74    case Conditional(condition, then, otherwise) => [condition, then, otherwise]75  }76}77