bug#61142: 回复: bug#61142: 29.0.60; java-ts-mode - Wrong indentation for the body of multiple lines conditions

[Theodor Thornhill via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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Theodor Thornhill <theo@thornhill.no> writes:

> Eli Zaretskii <eliz@gnu.org> writes:
>
>>> Cc: "61142@debbugs.gnu.org" <61142@debbugs.gnu.org>
>>> Date: Sun, 05 Feb 2023 20:19:19 +0100
>>> From:  Theodor Thornhill via "Bug reports for GNU Emacs,
>>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>>> 
>>> +(defvar c-ts-common-nestable-if-statement-p t
>>> +  "Does the current parser nest if-else statements?
>>> +
>>> +T if the current tree-sitter grammar nests the else if
>>> +statements, NIL otherwise.")
>>
>> A nit: we use t and nil, lowercase, to refer to these two symbols.
>>
>> Thanks.
>
> Thanks!
>
> Theo

I added some small tweaks, and will add the following as a test later:

```
public class Java {
    
    public Java(
        String foo) {
        this.foo = foo;
    }

    void foo(
        String foo) {

        for (var f : rs)
            return new String[]{
                "foo",
                "bar"
            };
        if (a == 0
            && b == 1
            && foo) {
            return 0;
        } else if (a == 1) {
            return 1;
        } else if (true)
            return 5;
        else {
            if (a == 0
                && b == 1
                && foo)
                while (true)
                    for (
                        ;;)
                        if (true)
                            return 5;
                        else if (false) {
                            return 6;
                        } else
                            if (true
                                && false)
                                return 6;
        }
    }
}
```

Even though its some pretty wild code, its indented correctly after this
patch.  I'll create something similar for C as well.

Theo


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From e2e931843936134f157ee6259167b6aae429da3a Mon Sep 17 00:00:00 2001
From: Theodor Thornhill <theo@thornhill.no>
Date: Sun, 5 Feb 2023 08:49:08 +0100
Subject: [PATCH] Use c-ts-common-statement-offset in java-ts-mode (bug#61142)

* lisp/progmodes/java-ts-mode.el (java-ts-mode--indent-rules): Add new
matchers to enable c-ts-common machinery.
(java-ts-mode): Add regexps.
* lisp/progmodes/c-ts-common.el (c-ts-common-statement-offset): Fix
typo in documentation and use the new if statement helpers.
(c-ts-common-if-statement-regexp): New defvar.
(c-ts-common-nestable-if-statement-p): New defvar.
(c-ts-common--fix-nestable-if-statement): New helper.
---
 lisp/progmodes/c-ts-common.el  | 33 ++++++++++++++++++++++++++++++-
 lisp/progmodes/java-ts-mode.el | 36 +++++++++++++++++++++++++---------
 2 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/lisp/progmodes/c-ts-common.el b/lisp/progmodes/c-ts-common.el
index 8729cae4ba..affb38139a 100644
--- a/lisp/progmodes/c-ts-common.el
+++ b/lisp/progmodes/c-ts-common.el
@@ -281,11 +281,22 @@ c-ts-common-indent-bracketless-type-regexp
 
 This can be nil, meaning such special handling is not needed.")
 
+(defvar c-ts-common-if-statement-regexp "if_statement"
+  "Regexp used to select an if statement in a C like language.
+
+This can be set to a different regexp if needed.")
+
+(defvar c-ts-common-nestable-if-statement-p t
+  "Does the current parser nest if-else statements?
+
+t if the current tree-sitter grammar nests the else if
+statements, nil otherwise.")
+
 (defun c-ts-common-statement-offset (node parent bol &rest _)
   "This anchor is used for children of a statement inside a block.
 
 This function basically counts the number of block nodes (i.e.,
-brackets) (defined by `c-ts-mode--indent-block-type-regexp')
+brackets) (defined by `c-ts-common-indent-block-type-regexp')
 between NODE and the root node (not counting NODE itself), and
 multiply that by `c-ts-common-indent-offset'.
 
@@ -312,6 +323,9 @@ c-ts-common-statement-offset
     (while (if (eq node t)
                (setq node parent)
              node)
+      ;; Subtract one indent level if the language nests
+      ;; if-statements and node is if_statement.
+      (setq level (c-ts-common--fix-nestable-if-statement level node))
       (when (string-match-p c-ts-common-indent-block-type-regexp
                             (treesit-node-type node))
         (cl-incf level)
@@ -354,6 +368,23 @@ c-ts-mode--fix-bracketless-indent
         (1+ level)
       level)))
 
+(defun c-ts-common--fix-nestable-if-statement (level node)
+  "Takes LEVEL and NODE and return adjusted LEVEL.
+Look at the type of NODE, when it is an if-statement node, as
+defined by `c-ts-common-if-statement-regexp' and its parent is
+also an if-statement node, subtract one level.  Otherwise return
+the value unchanged.  Whether or not if-statements are nestable
+is controlled by `c-ts-common-nestable-if-statement-p'."
+  ;; This fixes indentation for cases shown in bug#61142.
+  (or (and node
+           (treesit-node-parent node)
+           c-ts-common-nestable-if-statement-p
+           (equal (treesit-node-type node) c-ts-common-if-statement-regexp)
+           (equal (treesit-node-type (treesit-node-parent node))
+                  c-ts-common-if-statement-regexp)
+           (cl-decf level))
+      level))
+
 (provide 'c-ts-common)
 
 ;;; c-ts-common.el ends here
diff --git a/lisp/progmodes/java-ts-mode.el b/lisp/progmodes/java-ts-mode.el
index b9f7894095..1d7bdb0722 100644
--- a/lisp/progmodes/java-ts-mode.el
+++ b/lisp/progmodes/java-ts-mode.el
@@ -70,22 +70,25 @@ java-ts-mode--syntax-table
 (defvar java-ts-mode--indent-rules
   `((java
      ((parent-is "program") point-min 0)
-     ((node-is "}") (and parent parent-bol) 0)
+     ((match "}" "element_value_array_initializer")
+      parent-bol 0)
+     ((node-is "}") point-min c-ts-common-statement-offset)
      ((node-is ")") parent-bol 0)
+     ((node-is "else") parent-bol 0)
      ((node-is "]") parent-bol 0)
      ((and (parent-is "comment") c-ts-common-looking-at-star)
       c-ts-common-comment-start-after-first-star -1)
      ((parent-is "comment") prev-adaptive-prefix 0)
      ((parent-is "text_block") no-indent)
-     ((parent-is "class_body") parent-bol java-ts-mode-indent-offset)
+     ((parent-is "class_body") point-min c-ts-common-statement-offset)
      ((parent-is "array_initializer") parent-bol java-ts-mode-indent-offset)
-     ((parent-is "annotation_type_body") parent-bol java-ts-mode-indent-offset)
-     ((parent-is "interface_body") parent-bol java-ts-mode-indent-offset)
-     ((parent-is "constructor_body") parent-bol java-ts-mode-indent-offset)
+     ((parent-is "annotation_type_body") point-min c-ts-common-statement-offset)
+     ((parent-is "interface_body") point-min c-ts-common-statement-offset)
+     ((parent-is "constructor_body") point-min c-ts-common-statement-offset)
      ((parent-is "enum_body_declarations") parent-bol 0)
-     ((parent-is "enum_body") parent-bol java-ts-mode-indent-offset)
-     ((parent-is "switch_block") parent-bol java-ts-mode-indent-offset)
-     ((parent-is "record_declaration_body") parent-bol java-ts-mode-indent-offset)
+     ((parent-is "enum_body") point-min c-ts-common-statement-offset)
+     ((parent-is "switch_block") point-min c-ts-common-statement-offset)
+     ((parent-is "record_declaration_body") point-min c-ts-common-statement-offset)
      ((query "(method_declaration (block _ @indent))") parent-bol java-ts-mode-indent-offset)
      ((query "(method_declaration (block (_) @indent))") parent-bol java-ts-mode-indent-offset)
      ((parent-is "local_variable_declaration") parent-bol java-ts-mode-indent-offset)
@@ -118,7 +121,7 @@ java-ts-mode--indent-rules
      ((parent-is "case_statement") parent-bol java-ts-mode-indent-offset)
      ((parent-is "labeled_statement") parent-bol java-ts-mode-indent-offset)
      ((parent-is "do_statement") parent-bol java-ts-mode-indent-offset)
-     ((parent-is "block") (and parent parent-bol) java-ts-mode-indent-offset)))
+     ((parent-is "block") point-min c-ts-common-statement-offset)))
   "Tree-sitter indent rules.")
 
 (defvar java-ts-mode--keywords
@@ -300,6 +303,21 @@ java-ts-mode
   (c-ts-common-comment-setup)
 
   ;; Indent.
+  (setq-local c-ts-common-indent-block-type-regexp
+              (regexp-opt '("class_body"
+                            "array_initializer"
+                            "constructor_body"
+                            "annotation_type_body"
+                            "interface_body"
+                            "enum_body"
+                            "switch_block"
+                            "record_declaration_body"
+                            "block")))
+  (setq-local c-ts-common-indent-bracketless-type-regexp
+              (regexp-opt '("if_statement"
+                            "for_statement"
+                            "while_statement")))
+  (setq-local c-ts-common-indent-offset 'java-ts-mode-indent-offset)
   (setq-local treesit-simple-indent-rules java-ts-mode--indent-rules)
 
   ;; Electric
-- 
2.34.1