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implemented break

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This commit is contained in:
Moritz Gmeiner 2024-08-27 02:46:17 +02:00
commit e288a626fd
6 changed files with 84 additions and 72 deletions
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9
lib/error.ml
View file

@ -21,12 +21,17 @@ module ParserError = struct
Printf.printf "ParserError at line %d, column %d: %s\n" e.pos.line e.pos.col e.msg
end
type runtime_error = { pos : code_pos; msg : string }
type runtime_error = { pos : code_pos; msg : string; is_break : bool }
module RuntimeError = struct
type t = parser_error
let make (pos : code_pos) (msg : string) : runtime_error = { pos; msg }
let make (pos : code_pos) (msg : string) : runtime_error = { pos; msg; is_break = false }
let break () : runtime_error =
let pos = { line = -1; col = -1 } in
let msg = "" in
{ pos; msg; is_break = true }
let print (e : runtime_error) =
Printf.printf "RuntimeError at line %d, column %d: %s\n" e.pos.line e.pos.col e.msg

59
lib/interpreter.ml
View file

@ -13,18 +13,18 @@ let rec interpret_expr (env : environment) (expr_node : expr_node) :
(lox_value, runtime_error) result =
let { pos; expr } = expr_node in
match expr with
| Literal literal -> Ok (value_of_literal literal)
| Literal literal -> value_of_literal literal |> Result.ok
| Variable name -> (
let value_opt = Env.get env name in
match value_opt with
| Some x -> Ok x
| None ->
let msg = Printf.sprintf "name \"%s\" is not defined" name in
Error (RuntimeError.make pos msg))
RuntimeError.make pos msg |> Result.error)
| Assignment { name; expr } ->
if not (Env.is_defined env name) then
let msg = Printf.sprintf "tried to assign to undefined variable %s" name in
Error (RuntimeError.make pos msg)
RuntimeError.make pos msg |> Result.error
else
let* value = interpret_expr env expr in
Env.update env name value;
@ -32,44 +32,44 @@ let rec interpret_expr (env : environment) (expr_node : expr_node) :
| Unary { op; expr } -> (
let* expr = interpret_expr env expr in
match (op, expr) with
| Neg, Number x -> Ok (Number (-.x))
| Not, Bool b -> Ok (Bool (not b))
| Neg, Number x -> Number (-.x) |> Result.ok
| Not, Bool b -> Bool (not b) |> Result.ok
| _, _ ->
let msg =
Printf.sprintf "Invalid operant of type %s to operator %s"
(type_string_of_lox_value expr) (show_unary_op op)
in
Error (RuntimeError.make pos msg))
RuntimeError.make pos msg |> Result.error)
| Binary { op; left; right } -> (
let* left = interpret_expr env left in
let* right = interpret_expr env right in
match (left, op, right) with
| String a, Plus, String b -> Ok (String (a ^ b))
| Number x, Plus, Number y -> Ok (Number (x +. y))
| Number x, Minus, Number y -> Ok (Number (x -. y))
| Number x, Mul, Number y -> Ok (Number (x *. y))
| String a, Plus, String b -> String (a ^ b) |> Result.ok
| Number x, Plus, Number y -> Number (x +. y) |> Result.ok
| Number x, Minus, Number y -> Number (x -. y) |> Result.ok
| Number x, Mul, Number y -> Number (x *. y) |> Result.ok
| Number x, Div, Number y ->
if y <> 0. then Ok (Number (x /. y))
if y <> 0. then Number (x /. y) |> Result.ok
else
let msg = "Division by 0" in
Error { pos; msg }
| Bool b, And, Bool c -> Ok (Bool (b && c))
| Bool b, Or, Bool c -> Ok (Bool (b || c))
RuntimeError.make pos msg |> Result.error
| Bool b, And, Bool c -> Bool (b && c) |> Result.ok
| Bool b, Or, Bool c -> Bool (b || c) |> Result.ok
| _, Equal, _ -> Ok (Bool (left = right))
| Number x, Greater, Number y -> Ok (Bool (x > y))
| Number x, GreaterEqual, Number y -> Ok (Bool (x >= y))
| Number x, Less, Number y -> Ok (Bool (x < y))
| Number x, LessEqual, Number y -> Ok (Bool (x <= y))
| String a, Greater, String b -> Ok (Bool (a > b))
| String a, GreaterEqual, String b -> Ok (Bool (a >= b))
| String a, Less, String b -> Ok (Bool (a < b))
| String a, LessEqual, String b -> Ok (Bool (a <= b))
| Number x, Greater, Number y -> Bool (x > y) |> Result.ok
| Number x, GreaterEqual, Number y -> Bool (x >= y) |> Result.ok
| Number x, Less, Number y -> Bool (x < y) |> Result.ok
| Number x, LessEqual, Number y -> Bool (x <= y) |> Result.ok
| String a, Greater, String b -> Bool (a > b) |> Result.ok
| String a, GreaterEqual, String b -> Bool (a >= b) |> Result.ok
| String a, Less, String b -> Bool (a < b) |> Result.ok
| String a, LessEqual, String b -> Bool (a <= b) |> Result.ok
| _, _, _ ->
let msg =
Printf.sprintf "Invalid operands of type %s and %s to operator %s"
(type_string_of_lox_value left) (type_string_of_lox_value right) (show_binary_op op)
in
Error { pos; msg })
RuntimeError.make pos msg |> Result.error)
| Logical { op; left; right } -> (
let* left = interpret_expr env left in
match (op, lox_value_to_bool left) with
@ -83,6 +83,10 @@ let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runt
| Expr expr ->
let* _ = interpret_expr env expr in
Ok ()
| Break ->
(* print_endline "break!";
Ok () (* TODO *) *)
RuntimeError.break () |> Result.error
| Print expr ->
let* value = interpret_expr env expr in
print_endline (Value.string_of_lox_value value);
@ -93,7 +97,7 @@ let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runt
if success then Ok ()
else
let msg = Printf.sprintf "Tried to define %s, but was already defined" name in
Error (RuntimeError.make pos msg)
RuntimeError.make pos msg |> Result.error
| Block stmts ->
let env = Env.enter env in
let rec _interpret stmts =
@ -113,6 +117,9 @@ let rec interpret_stmt (env : environment) (stmt_node : stmt_node) : (unit, runt
let* cond = interpret_expr env cond in
let cond = lox_value_to_bool cond in
if cond then
let* _ = interpret_stmt env body in
interpret_stmt env stmt_node
let result = interpret_stmt env body in
match result with
| Error { is_break = true; _ } -> Ok ()
| Error e -> Error e
| _ -> interpret_stmt env stmt_node
else Ok ()

11
lib/lexer.ml
View file

@ -14,7 +14,7 @@ open Error
| String of string
| Number of float
| And | Class | Else | False | Fun | For | If | Nil | Or | Print | Return | Super | This | True
| And | Break | Class | Else | False | Fun | For | If | Nil | Or | Print | Return | Super | This | True
| Var | While
| Comment of string
@ -29,10 +29,11 @@ let keywords =
Hashtbl.add keywords s tt;
keywords
in
keywords |> insert "and" And |> insert "class" Class |> insert "else" Else |> insert "false" False
|> insert "for" For |> insert "fun" Fun |> insert "if" If |> insert "nil" Nil |> insert "or" Or
|> insert "print" Print |> insert "return" Return |> insert "super" Super |> insert "this" This
|> insert "true" True |> insert "var" Var |> insert "while" While
keywords |> insert "and" And |> insert "break" Break |> insert "class" Class |> insert "else" Else
|> insert "false" False |> insert "for" For |> insert "fun" Fun |> insert "if" If
|> insert "nil" Nil |> insert "or" Or |> insert "print" Print |> insert "return" Return
|> insert "super" Super |> insert "this" This |> insert "true" True |> insert "var" Var
|> insert "while" While
type token = { token_type : token_type; pos : code_pos }

33
lib/lexer.mli
View file

@ -22,6 +22,7 @@ type token_type =
| String of string
| Number of float
| And
| Break
| Class
| Else
| False
@ -50,36 +51,4 @@ val show_token : token -> string
type lexer_result = (token list, Error.lexer_error list) result
(* type state = {
source : string;
start_pos : int;
cur_pos : int;
tokens_rev : token list;
errors_rev : Error.lexer_error list;
line : int;
col : int;
}
module State : sig
type t = state
val is_digit : char -> bool
val is_alpha : char -> bool
val is_alphanum : char -> bool
val is_identifier : char -> bool
val is_at_end : state -> bool
val get_lexeme : state -> int -> int -> string
val advance : state -> char * state
val peek : state -> char option
val advance_if : char -> state -> bool * state
val advance_until : char -> state -> bool * state
val advance_while : (char -> bool) -> state -> state
val last_char : state -> char
val append_token : Error.code_pos -> token_type -> state -> state
val append_error : Error.code_pos -> string -> state -> state
val parse_number : state -> state
val parse_keyword_or_identifier : state -> state
val parse_block_commend : state -> state
val tokenize_rec : state -> state
end *)
val tokenize : string -> lexer_result

36
lib/parser.ml
View file

@ -8,10 +8,18 @@ open Stmt
type parse_result = (stmt_node list, parser_error list) result
type stmt_result = (stmt_node, parser_error) result
type expr_result = (expr_node, parser_error) result
type state = { tokens : token list }
type state = { tokens : token list; is_in_loop : bool }
let with_is_in_loop (f : state ref -> stmt_result) (state : state ref) : stmt_result =
let was_in_loop = !state.is_in_loop in
state := { !state with is_in_loop = true };
let result = f state in
state := { !state with is_in_loop = was_in_loop };
result
let make_state tokens = ref { tokens; is_in_loop = false }
let is_at_end state = (List.hd !state.tokens).token_type = Eof
let advance state = state := { tokens = List.tl !state.tokens }
let advance state = state := { !state with tokens = List.tl !state.tokens }
let next state =
assert (not ((List.hd !state.tokens).token_type = Eof));
@ -257,7 +265,12 @@ and while_loop (state : state ref) : stmt_result =
let* _ = consume state LeftParen in
let* cond = expression state in
let* _ = consume state RightParen in
let* body = statement state in
(* let was_in_loop = !state.is_in_loop in
state := { !state with is_in_loop = true };
let body = statement state in
state := { !state with is_in_loop = was_in_loop };
let* body = body in *)
let* body = with_is_in_loop statement state in
make_while pos cond body |> Result.ok
and for_loop (state : state ref) : stmt_result =
@ -287,7 +300,12 @@ and for_loop (state : state ref) : stmt_result =
| _ -> expression state |> Result.map Option.some
in
let* _ = consume state RightParen in
let* body = statement state in
(* let was_in_loop = !state.is_in_loop in
state := { !state with is_in_loop = true };
let body = statement state in
state := { !state with is_in_loop = was_in_loop };
let* body = body in *)
let* body = with_is_in_loop statement state in
let body =
match update with
| Some update ->
@ -311,6 +329,14 @@ and expr_stmt (state : state ref) : stmt_result =
and statement (state : state ref) : stmt_result =
let pos = cur_pos state in
match peek_tt state with
| Break ->
if !state.is_in_loop then (
advance state;
let* _ = consume state Semicolon in
make_break pos |> Result.ok)
else
let msg = "Can use break only in loops" in
ParserError.make pos msg |> Result.error
| Print ->
advance state;
let* expr = expression state in
@ -371,5 +397,5 @@ let parse (tokens : token list) : parse_result =
let tokens =
List.filter (fun tok -> match tok.token_type with Comment _ -> false | _ -> true) tokens
in
let state = ref { tokens } in
let state = make_state tokens in
parse_impl state

8
lib/stmt.ml
View file

@ -2,6 +2,7 @@ open Expr
type stmt =
| Expr of expr_node
| Break
| Print of expr_node
| VarDecl of { name : string; init : expr_node option }
| Block of stmt_node list
@ -16,6 +17,7 @@ let rec show_stmt ?(indent = 0) stmt =
let show_stmt_ind ?(add = 2) = show_stmt ~indent:(indent + add) in
match stmt with
| Expr expr -> indent_s ^ "Expr\n" ^ show_expr_ind expr.expr
| Break -> indent_s ^ "Break"
| Print expr -> indent_s ^ "Print\n" ^ show_expr_ind expr.expr
| VarDecl { name; init } -> (
indent_s ^ "Var " ^ name
@ -26,10 +28,10 @@ let rec show_stmt ?(indent = 0) stmt =
in
indent_s ^ "Block\n" ^ stmts_s ^ indent_s ^ "End"
| If { cond; then_; else_ } ->
let cond_s = show_expr_ind cond.expr in
let cond_s = show_expr_ind ~add:4 cond.expr in
let then_s = show_stmt_ind ~add:4 then_.stmt in
let else_s = Option.map (fun stmt -> show_stmt_ind ~add:4 stmt.stmt) else_ in
indent_s ^ "If\n" ^ indent_s ^ " Cond" ^ cond_s ^ "\n" ^ indent_s ^ " Then\n" ^ then_s
indent_s ^ "If\n" ^ indent_s ^ " Cond\n" ^ cond_s ^ "\n" ^ indent_s ^ " Then\n" ^ then_s
^ if Option.is_some else_s then "\n" ^ indent_s ^ " Else\n" ^ Option.get else_s else ""
| While { cond; body } ->
let cond_s = show_expr_ind ~add:4 cond.expr in
@ -42,6 +44,8 @@ let make_stmt_node (pos : Error.code_pos) (stmt : stmt) : stmt_node = { stmt; po
let make_expr_stmt (pos : Error.code_pos) (expr : expr_node) : stmt_node =
Expr expr |> make_stmt_node pos
let make_break (pos : Error.code_pos) : stmt_node = Break |> make_stmt_node pos
let make_print (pos : Error.code_pos) (expr : expr_node) : stmt_node =
Print expr |> make_stmt_node pos