ocaml parser "values do not match" error - parsing

Question

IHello!
I'm trying to code a lexer and parser for computer algebric system.
When I'm compiling the code with my makefile, I have problems on the value of some functions.
Here is the code of function.ml :
(****************************************
* Type definitions
****************************************)
type operator = Plus | Minus | Times | Div | Power;;
type var = string;; (* e.g. "x", "y", etc. *)
type power = var * float;; (* var, raised_to, e.g. ("x", 3.) -> x^3. *)
type monomial = float * power list;; (* coefficient, list of power terms, e.g. (2., [("x", 1.); ("y", 3.)]) -> 2xy^3 *)
type polynomial = monomial list;; (* sum of monomials, e.g. [(2., [("x", 2.); ("y", 3.)]); (-1., [])] -> 2x^2y^3 - 1 *)
type frac = polynomial * polynomial;; (* numerator, denominator *)
type exp = frac * frac;; (* base, exponent *)
type term = Poly of polynomial
| Frac of frac
| Exp of exp;;
type expr = Leaf of term
| Node of operator * expr list;;
type eqn = expr * expr;;
(****************************************
* Lexer/Parser definitions
****************************************)
type token = PLUS | MINUS | TIMES | DIV | POWER | LPAREN | RPAREN | EQUALS
| FLOAT of float
| VAR of var
| EOF;;
Here is the code of lexer.mll :
{
open Function
}
let numeric = ['0' - '9']
let letter = ['a' - 'z' 'A' - 'Z']
rule main = parse
| [' ' '\t' '\n'] { main lexbuf } (* skip over whitespace *)
| "+" { PLUS }
| "-" { MINUS }
| "*" { TIMES }
| "/" { DIV }
| "^" { POWER }
| "(" { LPAREN }
| ")" { RPAREN }
| "=" { EQUALS }
| ((numeric*) '.' (numeric+)) as n
{ FLOAT (float_of_string n) }
| (numeric+) as n
{ FLOAT (float_of_string n) }
| (letter numeric*) as n
{ VAR n }
| eof { EOF }
{
let lexer_main = main;;
let token_iterator_of_string s =
let rec lbuf = Lexing.from_string s
in fun () -> lexer_main lbuf;;
let token_list_of_string s =
let rec lbuf = Lexing.from_string s
and token_list_aux () =
let token = lexer_main lbuf in
if token = EOF then
[]
else
token :: token_list_aux ()
in token_list_aux ();;
}
Here is the code of parser.mly :
%{
open Function
%}
%token PLUS MINUS TIMES DIV POWER LPAREN RPAREN EQUALS EOF
%token <float> FLOAT
%token <Function.var> VAR
%start yacc_eqn
%start yacc_expr
%type <Function.eqn> yacc_eqn
%type <Function.expr> yacc_expr
%%
yacc_eqn:
exp EQUALS exp EOF { ($1, $3) }
yacc_expr:
exp EOF { $1 }
exp:
op1 { $1 }
op1:
op2 { $1 }
| op1 PLUS op2 { Node(Plus, [$1; $3]) }
| op1 MINUS op2 { Node(Minus, [$1; $3]) }
op2:
op3 { $1 }
| op2 TIMES op3 { Node(Times, [$1; $3]) }
| op2 DIV op3 { Node(Div, [$1; $3]) }
op3:
op4 { $1 }
| op3 op4 { Node(Times, [$1; $2]) }
op4:
leaf { $1 }
| op4 POWER leaf { Node(Power, [$1; $3]) }
leaf:
atom { $1 }
| LPAREN exp RPAREN { $2 }
atom:
VAR { Leaf(Poly(poly_of_var $1)) }
| FLOAT { Leaf(Poly(poly_of_float $1)) }
%%
let eqn_of_string s = yacc_eqn Lexer.lexer_main (Lexing.from_string s);;
let expr_of_string s = yacc_expr Lexer.lexer_main (Lexing.from_string s);;
let parse_eqn = eqn_of_string;;
let parse_expr = expr_of_string;;
The problem is that in the parser.mli which is create with the makefile, the value of yacc_eqn and yacc_expr are :
val yacc_eqn :
(Lexing.lexbuf -> token) -> Lexing.lexbuf -> Function.eqn
val yacc_expr :
(Lexing.lexbuf -> token) -> Lexing.lexbuf -> Function.expr
And I have the following error :
The implementation parser.ml does not match the interface parser.cmi:
Values do not match:
val yacc_eqn :
(Lexing.lexbuf -> Function.token) -> Lexing.lexbuf -> Function.eqn
is not included in
val yacc_eqn :
(Lexing.lexbuf -> token) -> Lexing.lexbuf -> Function.eqn
I think the solution might be to something like a cast, but I have stricly no idea how to do that ... Anyone help ?
Thanks in advance !