feat: basic parsing for expressions

2 files changed, 52 insertions, 18 deletions

diff --git a/src/index.ts b/src/index.ts
index 95a5411..75bc1af 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,19 +6,36 @@ import {
   integer,
   many1,
   mapTo,
+  matchChar,
   optional,
   or,
   pair,
+  Parser,
   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 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))
 // export const optional = mapTo(symbol('?'), constant({ tag: 'Optional' } as Expr))
 // export const zeroOrMore = mapTo(symbol('*'), constant({ tag: 'ZeroOrMore' } as Expr))
 // export const oneOrMore = mapTo(symbol('+'), constant({ tag: 'OneOrMore' } as Expr))
@@ -32,18 +49,32 @@ type Expr =
   | { tag: 'NextItem' }
   | { tag: 'AnyItem' }
   | { tag: 'Or' }
-  | { tag: 'String' }
-  | { tag: 'Number' }
-  | { tag: 'Bool' }
+  | { tag: 'AnyString' }
+  | { tag: 'AnyNumber' }
+  | { tag: 'AnyBool' }
   | { tag: 'Truthy' }
   | { tag: 'Falsey' }
+  | { tag: 'Group'; exprs: Expr[] }
 
-export const expressionP = or([
-  symbol('fuck'),
-  mapTo(many1(digit), (j) => j.join('')),
-])
+export const expressionP: Parser<Expr> = (input: string) =>
+  pipe(
+    input,
+    or([
+      mapTo(
+        delimited(symbol('('), many1(expressionP), symbol(')')),
+        (exprs) => ({ tag: 'Group', exprs })
+      ),
+      nextItem,
+      anyItem,
+      anyString,
+      anyNumber,
+      anyBool,
+      truthy,
+      falsey,
+    ])
+  )
 
-export const parser = pair(pair(optional(start), expressionP), optional(end))
+export const parser = tuple3(optional(start), many1(expressionP), optional(end))
 
 /*
 
diff --git a/src/parser.ts b/src/parser.ts
index 9baab8e..baa3e76 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -90,15 +90,12 @@ export const tab = matchChar('\t')
 export const whitespace = or([space, newline, tab])
 export const whitespaces0 = many0(whitespace)
 
-export const matchString = (s: string): Parser<string> =>
-  s === ''
-    ? constP('')
-    : flow(
-        matchChar(s.charAt(0)),
-        chain(([c, inp]) =>
-          pipe(inp, matchString(s.slice(1)), map(mapFst((s) => c + s)))
-        )
-      )
+export const matchString =
+  (s: string): Parser<string> =>
+  (input: string) =>
+    input.slice(0, s.length) === s
+      ? right([s, input.slice(s.length)])
+      : left([`Expected ${s} but got ${input.slice(0, 1)}`, input])
 
 export const symbol = (s: string): Parser<string> =>
   delimited(whitespaces0, matchString(s), whitespaces0)
@@ -131,3 +128,9 @@ export const pair = <A, B>(a: Parser<A>, b: Parser<B>): Parser<[A, B]> =>
     a,
     andThen((ra) => mapTo(b, (rb) => [ra, rb]))
   )
+
+export const tuple3 = <A, B, C>(
+  a: Parser<A>,
+  b: Parser<B>,
+  c: Parser<C>
+): Parser<[A, B, C]> => mapTo(pair(pair(a, b), c), ([[a, b], c]) => [a, b, c])