add string support

ast.ml

@@ -3,6 +3,7 @@ type type_t =
   | Void_t
   | Int_t
   | Bool_t
+  | Str_t
   | Func_t of type_t * type_t list
 
 module Syntax = struct
@@ -12,6 +13,7 @@ module Syntax = struct
     | Void
     | Int of int
     | Bool of bool
+    | Str of string
 
   type expr =
     | Val of
@@ -79,6 +81,7 @@ module V1 = struct
     | Void
     | Int of int
     | Bool of bool
+    | Str of string
 end
 
 module V2 = struct
@@ -86,6 +89,7 @@ module V2 = struct
     | Void
     | Int of int
     | Bool of bool
+    | Data of string
 end
 
 module IR (P : Parameters) = struct

compiler.ml

@@ -15,6 +15,7 @@ let compile_value = function
   | Void -> [ Li (V0, 0) ]
   | Int n -> [ Li (V0, n) ]
   | Bool b -> [ Li (V0, if b then 1 else 0) ]
+  | Data l -> [ La (V0, Lbl l) ]
 ;;
 
 let rec compile_expr env = function

errors.ml

@@ -3,6 +3,7 @@ open Lexing
 
 exception LexerError of char
 exception SemanticsError of string * Lexing.position
+exception SyntaxError of string
 
 let err msg pos =
   Printf.eprintf
@@ -18,6 +19,7 @@ let rec string_of_type_t = function
   | Void_t -> "void"
   | Int_t -> "int"
   | Bool_t -> "bool"
+  | Str_t -> "str"
   | Func_t (r, a) ->
     (if List.length a > 1 then "(" else "")
     ^ String.concat ", " (List.map string_of_type_t a)

lexer.mll

@@ -19,6 +19,7 @@ rule token = parse
   | "int"         { Ltype (Int_t) }
   | "bool"        { Ltype (Bool_t) }
   | "void"        { Ltype (Void_t) }
+  | "str"         { Ltype (Str_t) }
   | '{'           { Lbracedeb }
   | '}'           { Lbracefin }
   | '('           { Lpardeb }
@@ -30,6 +31,7 @@ rule token = parse
   | '-'           { Lsub }
   | '*'           { Lmul }
   | '/'           { Ldiv }
+  | '"'           { read_string (Buffer.create 16) lexbuf }
   | ident as i    { Lvar i }
   | '#'           { comment lexbuf }
   | _ as c        { raise (LexerError c) }
@@ -38,3 +40,11 @@ and comment = parse
   | eof   { Lend }
   | '\n'  { Lexing.new_line lexbuf; token lexbuf }
   | _     { comment lexbuf }
+
+and read_string buffer = parse
+  | '"'           { Lstr (Buffer.contents buffer) }
+  | [^ '"' '\\']+ { Buffer.add_string buffer (Lexing.lexeme lexbuf)
+                  ; read_string buffer lexbuf
+                  }
+  | _ as c        { raise (LexerError c) }
+  | eof           { raise (SyntaxError "String is not terminated") }

main.ml

@@ -18,6 +18,7 @@ let () =
   with
   | LexerError c ->
     err (Printf.sprintf "Unrecognized char \"%c\"" c) (Lexing.lexeme_start_p buf)
+  | SyntaxError s -> err (Printf.sprintf "%s" s) (Lexing.lexeme_start_p buf)
   | Parser.Error -> err "Syntax error" (Lexing.lexeme_start_p buf)
   | SemanticsError (msg, pos) -> err msg pos
 ;;

parser.mly

@@ -5,6 +5,7 @@
 
 %token <int> Lint
 %token <bool> Lbool
+%token <string> Lstr
 %token <Ast.type_t> Ltype
 %token <string> Lvar
 %token Lend Lassign Lsc Lreturn
@@ -15,7 +16,7 @@
 %left Ladd Lsub Lmul Ldiv
 
 %left Lbracedeb Lparfin Lbracefin Lreturn
-%left Ltype Lbool Lint Lvar
+%left Ltype Lbool Lint Lvar Lstr
 
 %start prog
 
@@ -117,6 +118,11 @@ expr:
     Val { value = Bool (b) ; pos = $startpos(b) }
   }
 
+  /* string */
+  | s = Lstr {
+    Val { value = Str (s) ; pos = $startpos(s) }
+  }
+
   /* Variable */
   | v = Lvar {
     Var { name = v ; pos = $startpos(v) }

semantics.ml

@@ -8,6 +8,7 @@ let analyze_value = function
   | Syntax.Void -> Void, Void_t
   | Syntax.Int n -> Int n, Int_t
   | Syntax.Bool b -> Bool b, Bool_t
+  | Syntax.Str s -> Str s, Str_t
 ;;
 
 let rec analyze_expr env ua t = function

simplifier.ml

@@ -1,10 +1,15 @@
 open Ast
 
 let collect_constant_strings code =
+  let counter = ref 0 in
   let ccs_value = function
     | V1.Void -> V2.Void, []
     | V1.Bool b -> V2.Bool b, []
     | V1.Int n -> V2.Int n, []
+    | V1.Str s ->
+      incr counter;
+      let lbl = "str" ^ string_of_int !counter in
+      V2.Data lbl, [ lbl, Mips.Asciiz s ]
   in
   let rec ccs_expr = function
     | IR1.Val v ->

tests/20_str.test

@@ -0,0 +1,3 @@
+void main () {
+    str a = "bonjour!";
+}

tests/21_bad-str.test

@@ -0,0 +1,4 @@
+void main () {
+    # Error on line 3 col 28: String is not terminated.
+    str a = "au revoir !;
+}