package yuujinchou

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Module Yuujinchou.ActionSource

The Action module implements the engine running the patterns.

The engine tries to preserve physical equality whenever feasible. For example, if the trie t has a binding at x, the pattern Pattern.renaming["x"] ["x"] on t will return the original t.

Matching

Sourcetype nonrec ('a, 'error) result = ('a Trie.t, [> `BindingNotFound of Pattern.path ] as 'error) result

The type of the result. The error `BindingNotFound means that the engine expected at least one binding under path but could not find it.

Sourceval run : ?rev_prefix:Pattern.path -> union:(rev_path:Pattern.path -> 'a -> 'a -> 'a) -> unit Pattern.t -> 'a Trie.t -> ('a, 'error) result

run ~rev_prefix ~union pattern trie runs the pattern on the trie and return the transformed trie. It ignores patterns created by Pattern.hook.

  • parameter rev_prefix

    The prefix prepended to any path sent to union and any path in the error reporting, but in reverse. The default is the empty unit path ([]).

  • parameter union

    The resolver for two conflicting bindings sharing the same name. Patterns such as Pattern.renaming and Pattern.union could lead to conflicting bindings, and union ~rev_path x y should return the resolution of x and y at the (reversed) path rev_path.

  • returns

    The new trie after the transformation. Error (`BindingNotFound p) means the transformation failed because of the absence of expected bindings. For example, the pattern Pattern.except["x"; "y"] expects that there was already something under the subtree at x.y. If there were actually no names with the prefix x.y, then the pattern will trigger the error `BindingNotFound ["x"; "y"]. The path p is only an approximation---the user might have intended to hide the binding at ["x"; "y"; "z"], a binding under ["x"; "y"], but the engine would never know the user's true intention.

Sourceval run_with_hooks : ?rev_prefix:Pattern.path -> union:(rev_path:Pattern.path -> 'a -> 'a -> 'a) -> hooks:('hook -> rev_prefix:Pattern.path -> 'a Trie.t -> ('a, 'error) result) -> 'hook Pattern.t -> 'a Trie.t -> ('a, 'error) result

run_with_hooks ~rev_prefix ~hooks ~union pattern trie runs the pattern on the trie and return the transformed trie. It is similar to run but accepts a new argument hooks to handle the patterns created by Pattern.hook.

  • parameter hooks

    The hooks that will be triggered by patterns created by Pattern.hook. When the engine encounters the pattern Pattern.hookh, it will call hooks h ~rev_path:p t on the current trie where p is the path (in reverse) and t is the subtrie at p.

Pretty Printers

Sourceval pp_path : Format.formatter -> Pattern.path -> unit

Pretty printer for path.