From 9b9b7633c13aa9f99ffb5683374f5c11a4966a93 Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <rekado@elephly.net>
Date: Mon, 3 Jun 2019 17:36:36 +0200
Subject: modules: completer: Simplify.

* modules/language/python/completer.scm (aif): Remove macro.
(complete-fkn): Simplify, comment, and add docstring; rename...
(complete-python): ...to this.
(reg): Rename this variable...
(dotted-words-regexp): ...to this.
---
 modules/language/python/completer.scm | 76 +++++++++++++++++------------------
 modules/language/python/spec.scm      |  2 +-
 2 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/modules/language/python/completer.scm b/modules/language/python/completer.scm
index 047248e..a3d3677 100644
--- a/modules/language/python/completer.scm
+++ b/modules/language/python/completer.scm
@@ -2,47 +2,47 @@
   #:use-module (language python list)
   #:use-module (language python dir)
   #:use-module (system base language)
+  #:use-module (ice-9 match)
   #:use-module (ice-9 regex)
-  #:export (complete-fkn))
+  #:export (complete-python))
 
-(define-syntax-rule (aif it p x y) (let ((it p)) (if it x y)))
+(define (old)
+  (@@ (ice-9 readline) *readline-completion-function*))
 
-(define (old) (@@ (ice-9 readline) *readline-completion-function*))
+(define dotted-words-regexp "(\\w+(\\.\\w+)*)\\.(\\w*)$")
 
-(define reg  "(\\w+(\\.\\w+)*)\\.(\\w*)$")
+(define (complete-python proc)
+  "Return a readline completion procedure for completing dotted Python
+names."
+  (define completions '())
+  (define regexp #f)
+  (define prefix "")
+  (letrec ((complete
+            (lambda (text continue?)
+              (cond
+               (continue?
+                (match completions
+                  (() #f)
+                  ((candidate . rest)
+                   (set! completions rest)
+                   (if (string-match regexp candidate)
+                       (string-append prefix "." candidate)
+                       (complete text #t)))))
 
-(define (complete-fkn eval)
-  (let ((old     (old))
-        (strs   '()   )
-        (pp      ""   )
-        (regexp  #f   ))
-    (letrec
-        ((compl
-          (lambda (text continue?)
-            (if continue?
-                (if (null? strs)
-                    #f
-                    (let ((str (car strs)))
-                      (set! strs (cdr strs))
-                      (if (string-match regexp str)
-                          (string-append pp "." str)
-                          (compl text #t))))
-                (if (and (equal? (language-name (current-language)) 'python)
-                         (in "." text))
-                    (aif it (string-match reg text)
-                         (let* ((n (match:count     it))
-                                (p (match:substring it 1))
-                                (t (match:substring it (- n 1)))
-                                (d (to-list (dir (eval p)))))
-                           (begin
-                             (set! strs d)
-                             (set! pp   p)
-                             (set! regexp (string-append
-                                           "^" (if (string-null? t)
-                                                   "[^_]"
-                                                   (regexp-quote t))))
-                             (compl text #t)))
-                         #f)
-                    (old text continue?))))))
-      compl)))
+               ;; Initialize completions
+               ((and (equal? (language-name (current-language)) 'python)
+                     (in "." text))
+                (and=> (string-match dotted-words-regexp text)
+                       (lambda (m)
+                         (let ((head (match:substring m 1))
+                               (tail (match:substring m (1- (match:count m)))))
+                           (set! prefix head)
+                           (set! completions (to-list (dir (proc head))))
+                           (set! regexp (string-append
+                                         "^" (if (string-null? tail)
+                                                 "[^_]"
+                                                 (regexp-quote tail))))
+                           (complete text #t)))))
+               (else ((old) text continue?))))))
+    complete))
   
diff --git a/modules/language/python/spec.scm b/modules/language/python/spec.scm
index ea545ac..a267f72 100644
--- a/modules/language/python/spec.scm
+++ b/modules/language/python/spec.scm
@@ -71,7 +71,7 @@
 (catch #t
   (lambda ()
     (set! (@@ (ice-9 readline) *readline-completion-function*)
-      (complete-fkn e)))
+      (complete-python e)))
   (lambda x #f))
 
 (define-language python
-- 
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