TypeScript で型検査器を作る / Implementing a type checker with TypeScript

1. 5ZQF4DSJQU
   ͰܕݕࠪثΛ࡞Δ ܕษڧձ
   
   
2. ܕݕࠪث w ͋Δܭࢉମܥʹ͓͚Δ߲ͷܕΛಋग़͢Δ
   w ܕ෇͚نଇʹ౰ͯ͸·Βͳ͍߲͕ଘࡏ͢Δ࣌͸
 ΤϥʔΛ౤͛Δ
3. +BWB4DSJQU
   ͷܕݕࠪثΛ ࡞ͬͯΈΔ w ඞཁʹഭΒΕͨͷͰʜʜ
   w ߏจ໦͸
   &TQSJNB
   ͱ͔Λ࢖ͬͯಘΔ͜ͱ͕Ͱ͖Δ
   w 5ZQF4DSJQU
   ͷܕ৘ใΛదٓ༗ޮ׆༻͢Δ
   w ؆୯ͷͨΊʹɺ߲͸෭࡞༻Λ࣋ͨͳ͍΋ͷͱ͢Δ
4. "45
   &YQMPSFS IUUQTBTUFYQMPSFSOFU
5. ܕ෇͚نଇͷྫ • true: boolean • t: string ∧ u: U → (t + u): string • t: T ∧ u: T → (t === u): boolean • t: { u: U } → t.u: U ˢΛͦͷ··࣮૷͢Ε͹
   0,
6. είʔϓ w ݱࡏݕ͍ࠪͯ͠Δ߲Ͱར༻Մೳͳม਺ͷҰཡΛ
 ͓࣋ͬͯ͘ඞཁ͕͋ΔͷͰɺ function typeOf(ast: ESTree.Node, scope: Var[]): Type Έ͍ͨͳײ͡ʹͳΔ
7. ΤϥʔΛूΊΔ w ܕ෇͚نଇʹ౰ͯ͸·Βͳ͍࣌ʹΤϥʔΛ౤͛Δ
 ͷͰ͸ͳ͘ɺจ຺ʹΤϥʔΛ௥Ճ͢Δ
   w ϝοηʔδ΍ιʔείʔυ্ͷ৔ॴΛ෇༩͢Δͱศར

   ΤσΟλʔͱ͔Ͱ੺ઢΛҾ͚Δ
8. શମ૾ function typeOf(ast: ESTree.Node, scope: Var[]) { switch (ast.type) { case ‘BinaryOperator’: // … case ‘…’: default: this.errors.push({ message: ‘…’, start: …, end: … }) } }