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Pattern-matching parsing

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This commit is contained in:
Dmitry Boulytchev 2018-05-01 02:57:09 +03:00
parent 3f40a66f43
commit de760a2b09
3 changed files with 50 additions and 5 deletions
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40
src/Language.ml
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@ -25,6 +25,7 @@ module Value =
| Array a -> a
| _ -> failwith "array value expected"
let sexp s vs = Sexp (s, vs)
let of_int n = Int n
let of_string s = String s
let of_array a = Array a
@ -226,16 +227,48 @@ module Expr =
module Stmt =
struct
(* Patterns in statements *)
module Pattern =
struct
(* The type for patterns *)
@type t =
(* wildcard "-" *) | Wildcard
(* S-expression *) | Sexp of string * t list
(* identifier *) | Ident of string
(* constant *) | Const of int
(* string *) | String of string
(* array *) | Array of t list
(* arbitrary array *) | IsArray
(* arbitrary string *) | IsString
with show
(* Pattern parser *)
ostap (
parse:
%"_" {Wildcard}
| "`" t:IDENT ps:(-"(" !(Util.list)[parse] -")")? {Sexp (t, match ps with None -> [] | Some ps -> ps)}
| x:IDENT {Ident x}
| n:DECIMAL {Const n}
| s:STRING {String s}
| a:(-"[" !(Util.list)[parse] -"]") {Array a}
| "#" "[" "]" {IsArray}
| "#" {IsString}
)
end
(* The type for statements *)
type t =
@type t =
(* assignment *) | Assign of string * Expr.t list * Expr.t
(* composition *) | Seq of t * t
(* empty statement *) | Skip
(* conditional *) | If of Expr.t * t * t
(* loop with a pre-condition *) | While of Expr.t * t
(* loop with a post-condition *) | Repeat of t * Expr.t
(* pattern-matching *) | Case of Expr.t * (Pattern.t * Expr.t option * t) list
(* return statement *) | Return of Expr.t option
(* call a procedure *) | Call of string * Expr.t list
(* call a procedure *) | Call of string * Expr.t list with show
(* Statement evaluator
@ -299,7 +332,8 @@ module Stmt =
Seq (i, While (c, Seq (b, s)))
}
| %"repeat" s:parse %"until" e:!(Expr.parse) {Repeat (s, e)}
| %"return" e:!(Expr.parse)? {Return e}
| %"return" e:!(Expr.parse)? {Return e}
| %"case" e:!(Expr.parse) %"of" bs:!(Util.listBy)[ostap ("|")][ostap (!(Pattern.parse) (-"when" !(Expr.parse))? parse)] %"esac" {Case (e, bs)}
| x:IDENT
s:(is:(-"[" !(Expr.parse) -"]")* ":=" e :!(Expr.parse) {Assign (x, is, e)} |
"(" args:!(Util.list0)[Expr.parse] ")" {Call (x, args)}