guess_lengths

wordsLib.guess_lengths : unit -> unit

Turns on word length guessing.

A call to guess_lengths adds a post-prcessing stage to the term parser: the function inst_word_lengths is used to instantiate type variables that are the return type of word_concat and word_extract.

Example

- load "wordsLib";
...
- show_types := true;
> val it = () : unit
- “(7 >< 5) a @@ (4 >< 0) a”;
<<HOL message: inventing new type variable names: 'a, 'b, 'c, 'd>>
> val it =
    “(((7 :num) >< (5 :num)) (a :bool['d]) :bool['a]) @@
      (((4 :num) >< (0 :num)) a :bool['b])” : term
- wordsLib.guess_lengths();
> val it = () : unit
- “(7 >< 5) a @@ (4 >< 0) a”;
<<HOL message: inventing new type variable names: 'a, 'b, 'c, 'd>>
<<HOL message: assigning word length(s): 'a <- 3, 'b <- 5 and 'c <- 8>>
> val it =
    “(((7 :num) >< (5 :num)) (a :bool['d]) :bool[3]) @@
      (((4 :num) >< (0 :num)) a :bool[5])” : term
- type_of it;
> val it = “:bool[8]” : hol_type

See also

wordsLib.inst_word_lengths, wordsLib.notify_on_word_length_guess