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|
import { constant, pipe } from 'fp-ts/function'
import { chain, fold, right } from 'fp-ts/lib/Either'
import { match } from './utils'
import {
delimited,
many1,
mapTo,
optional,
or,
Parser,
ParserResult,
symbol,
tuple3,
} from './parser'
export const start = mapTo(symbol('^'), constant({ tag: 'Start' } as Expr))
export const end = mapTo(symbol('$'), constant({ tag: 'End' } as Expr))
export const anyItem = mapTo(symbol('.'), constant({ tag: 'AnyItem' } as Expr))
export const nextItem = mapTo(
symbol(','),
constant({ tag: 'NextItem' } as Expr)
)
export const anyString = mapTo(
symbol('\\s'),
constant({ tag: 'AnyString' } as Expr)
)
export const anyNumber = mapTo(
symbol('\\n'),
constant({ tag: 'AnyNumber' } as Expr)
)
export const anyBool = mapTo(
symbol('\\b'),
constant({ tag: 'AnyBool' } as Expr)
)
export const truthy = mapTo(symbol('\\T'), constant({ tag: 'Truthy' } as Expr))
export const falsey = mapTo(symbol('\\F'), constant({ tag: 'Falsey' } as Expr))
type Expr =
| { tag: 'Start' }
| { tag: 'End' }
| { tag: 'Optional'; expr: Expr }
| { tag: 'OneOrMore'; expr: Expr }
| { tag: 'ZeroOrMore'; expr: Expr }
| { tag: 'NextItem' }
| { tag: 'AnyItem' }
| { tag: 'Or' }
| { tag: 'AnyString' }
| { tag: 'AnyNumber' }
| { tag: 'AnyBool' }
| { tag: 'Truthy' }
| { tag: 'Falsey' }
| { tag: 'Group'; exprs: Expr[] }
export const wrapQuantifiers: (e: ParserResult<Expr>) => ParserResult<Expr> =
chain(([expr, input]) =>
pipe(
input,
or([symbol('*'), symbol('+'), symbol('?')]),
fold(
() => right([expr, input]),
([c, inp]) =>
pipe(
c,
match<Expr, string>({
'*': () => ({ tag: 'ZeroOrMore', expr }),
'+': () => ({ tag: 'OneOrMore', expr }),
'?': () => ({ tag: 'Optional', expr }),
_: () => expr,
}),
(ex) => right([ex, inp])
)
)
)
)
export const expressionP: Parser<Expr> = (input: string) =>
pipe(
input,
or([
mapTo(
delimited(symbol('('), many1(expressionP), symbol(')')),
(exprs) => ({ tag: 'Group', exprs } as Expr)
),
nextItem,
anyItem,
anyString,
anyNumber,
anyBool,
truthy,
falsey,
]),
wrapQuantifiers
)
export const parser = tuple3(optional(start), many1(expressionP), optional(end))
/*
{3,6} => 3 to 6 instances
(> 5) => number greater than
(< 5) => number less than
[name x] => apply x on property `name`
| => or
/x/ => match regular expression (string values in list)
*/
|
