feat(wpcarro/compiler): Support string literal type

```
repl> "Hello, world"
String
repl> (fn x "testing")
a0 -> String
```

Change-Id: Ia76299a56aa4d2032c9a21277e2fddfb2e055831
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7079
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
This commit is contained in:
William Carroll 2022-10-24 17:53:21 -04:00 committed by wpcarro
parent 1e9c3955bf
commit ee235235b9
3 changed files with 34 additions and 5 deletions

View file

@ -5,6 +5,7 @@
*
* Helpers:
* symbol -> [-a-z]+
* string -> '"' [^"]* '"'
* boolean -> 'true' | 'false'
* integer -> [1-9][0-9]*
*
@ -13,7 +14,7 @@
* binding -> '(' 'let' symbol expr expr ')'
* funcdef -> '(' 'fn' symbol expr ')'
* funccall -> '(' ( symbol | funcdef) expr ')'
* literal -> boolean | integer
* literal -> string | boolean | integer
* variable -> symbol
*
* Example Usage:
@ -52,6 +53,17 @@ let tokenize (x : string) : token array =
while !i < String.length x do
match x.[!i] with
| ' ' -> i := !i + 1
(* strings *)
| '"' ->
let curr = ref "\"" in
i := !i + 1;
while x.[!i] != '"' do
curr := !curr ^ "?";
i := !i + 1
done;
curr := !curr ^ "\"";
Queue.push !curr q;
i := !i + 1
| '(' ->
Queue.push "(" q;
i := !i + 1
@ -95,7 +107,14 @@ let parse_literal (p : parser) : Types.value option =
| Some n ->
p#advance;
Some (ValueLiteral (LiteralInt n))
| _ -> parse_variable p)
| _ ->
if String.starts_with "\"" x then
begin
p#advance;
Some (ValueLiteral (LiteralString x))
end
else
parse_variable p)
| _ -> None
let rec parse_expression (p : parser) : Types.value option =
@ -144,7 +163,8 @@ let print_tokens (xs : string array) =
|> List.map (Printf.sprintf "\"%s\"")
|> String.concat ", "
|> Printf.sprintf "tokens: [ %s ]"
|> print_string |> print_newline
|> print_string
|> print_newline
let parse_language (x : string) : Types.value option =
let tokens = tokenize x in

View file

@ -29,6 +29,7 @@ let rec free_type_vars (t : _type) : set =
| TypeVariable k -> FromString.singleton k true
| TypeInt -> FromString.empty
| TypeBool -> FromString.empty
| TypeString -> FromString.empty
| TypeArrow (a, b) -> lww (free_type_vars a) (free_type_vars b)
let i : int ref = ref 0
@ -51,6 +52,7 @@ let rec instantiate (q : quantified_type) : _type =
match t with
| TypeInt -> TypeInt
| TypeBool -> TypeBool
| TypeString -> TypeString
| TypeVariable k ->
if List.exists (( == ) k) names then make_type_var () else TypeVariable k
| TypeArrow (a, b) ->
@ -83,6 +85,7 @@ let rec substitute_type (s : substitution) (t : _type) : _type =
| TypeArrow (a, b) -> TypeArrow (substitute_type s a, substitute_type s b)
| TypeInt -> TypeInt
| TypeBool -> TypeBool
| TypeString -> TypeString
let substitute_quantified_type (s : substitution) (q : quantified_type) : quantified_type =
let (QuantifiedType (names, t)) = q in
@ -102,6 +105,7 @@ let rec unify (a : _type) (b : _type) : substitution option =
match (a, b) with
| TypeInt, TypeInt -> Some FromString.empty
| TypeBool, TypeBool -> Some FromString.empty
| TypeString, TypeString -> Some FromString.empty
| TypeVariable k, _ -> Some (bind_var k b)
| _, TypeVariable k -> Some (bind_var k a)
| TypeArrow (a, b), TypeArrow (c, d) ->
@ -136,7 +140,8 @@ let rec infer (env : env) (x : value) : inference option =
| ValueLiteral lit -> (
match lit with
| LiteralInt _ -> Some (Inference (FromString.empty, TypeInt))
| LiteralBool _ -> Some (Inference (FromString.empty, TypeBool)))
| LiteralBool _ -> Some (Inference (FromString.empty, TypeBool))
| LiteralString _ -> Some (Inference (FromString.empty, TypeString)))
| ValueVariable k ->
let* v = FromString.find_opt k env in
Some (Inference (FromString.empty, instantiate v))

View file

@ -1,4 +1,7 @@
type literal = LiteralInt of int | LiteralBool of bool
type literal
= LiteralInt of int
| LiteralBool of bool
| LiteralString of string
(* Lambda Calculus definition *)
type value =
@ -14,6 +17,7 @@ module FromString = Map.Make (String)
type _type =
| TypeInt
| TypeBool
| TypeString
| TypeVariable of string
| TypeArrow of _type * _type