Re: How do I pass a variable defined in a wrapping let, to a lambda?

[Emanuel Berg]

Steinar Bang wrote:

> But it still didn't work. And the reason it didn't work is
> that filename didn't have a value set.
>
> If I replace the filename variable with a text constant[6],
> then the function works.
>
> But as far as I can tell, the function in uses variables
> defined in the wrapping (let) in the lambda...?

Dynamic/special scope?

But I see that you don't have that ... weird.

This works:

;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/geh.el

(defun add-one-f (term)
  (let ((tm term))
    (lambda () (1+ tm)) ))

(funcall (add-one-f 2)) ; 3

But not this:

;; this file:
;;   https://dataswamp.org/~incal/emacs-init/geh-dynamic.el

(defun add-two-f (term)
  (let ((tm term))
    (lambda () (+ 2 tm)) ))

(funcall (add-two-f 2)) ; Symbol’s value as variable is void: tm

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