;;; java-ts-mode.el --- tree-sitter support for Java -*- lexical-binding: t; -*-
;; Copyright (C) 2022 Free Software Foundation, Inc.
;; Author : Theodor Thornhill <theo@thornhill.no>
;; Maintainer : Theodor Thornhill <theo@thornhill.no>
;; Created : November 2022
;; Keywords : java languages tree-sitter
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;;
;;; Code:
(require 'treesit)
(eval-when-compile (require 'rx))
(declare-function treesit-parser-create "treesit.c")
(declare-function treesit-induce-sparse-tree "treesit.c")
(declare-function treesit-node-start "treesit.c")
(declare-function treesit-node-child-by-field-name "treesit.c")
(defcustom java-ts-mode-indent-offset 4
"Number of spaces for each indentation step in `java-ts-mode'."
:version "29.1"
:type 'integer
:safe 'integerp
:group 'java)
(defvar java-ts-mode--syntax-table
(let ((table (make-syntax-table)))
;; Taken from the cc-langs version
(modify-syntax-entry ?_ "_" table)
(modify-syntax-entry ?\\ "\\" table)
(modify-syntax-entry ?+ "." table)
(modify-syntax-entry ?- "." table)
(modify-syntax-entry ?= "." table)
(modify-syntax-entry ?% "." table)
(modify-syntax-entry ?< "." table)
(modify-syntax-entry ?> "." table)
(modify-syntax-entry ?& "." table)
(modify-syntax-entry ?| "." table)
(modify-syntax-entry ?\' "\"" table)
(modify-syntax-entry ?\240 "." table)
(modify-syntax-entry ?/ ". 124b" table)
(modify-syntax-entry ?* ". 23" table)
(modify-syntax-entry ?\n "> b" table)
(modify-syntax-entry ?\^m "> b" table)
(modify-syntax-entry ?@ "'" table)
table)
"Syntax table for `java-ts-mode'.")
(defvar java-ts-mode--indent-rules
`((java
((parent-is "program") parent-bol 0)
((node-is "}") (and parent parent-bol) 0)
((node-is ")") parent-bol 0)
((node-is "]") parent-bol 0)
((and (parent-is "comment") comment-end) comment-start -1)
((parent-is "comment") comment-start-skip 0)
((parent-is "text_block") no-indent)
((parent-is "class_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 "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)
((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 "variable_declarator") parent-bol java-ts-mode-indent-offset)
((parent-is "method_invocation") parent-bol java-ts-mode-indent-offset)
((parent-is "switch_rule") parent-bol java-ts-mode-indent-offset)
((parent-is "ternary_expression") parent-bol java-ts-mode-indent-offset)
((parent-is "lambda_expression") parent-bol java-ts-mode-indent-offset)
((parent-is "element_value_array_initializer") parent-bol java-ts-mode-indent-offset)
((parent-is "function_definition") parent-bol 0)
((parent-is "conditional_expression") first-sibling 0)
((parent-is "assignment_expression") parent-bol 2)
((parent-is "binary_expression") parent 0)
((parent-is "parenthesized_expression") first-sibling 1)
((parent-is "argument_list") parent-bol java-ts-mode-indent-offset)
((parent-is "annotation_argument_list") parent-bol java-ts-mode-indent-offset)
((parent-is "modifiers") parent-bol 0)
((parent-is "formal_parameters") parent-bol java-ts-mode-indent-offset)
((parent-is "formal_parameter") parent-bol 0)
((parent-is "init_declarator") parent-bol java-ts-mode-indent-offset)
((parent-is "if_statement") parent-bol java-ts-mode-indent-offset)
((parent-is "for_statement") parent-bol java-ts-mode-indent-offset)
((parent-is "while_statement") parent-bol java-ts-mode-indent-offset)
((parent-is "switch_statement") parent-bol java-ts-mode-indent-offset)
((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)))
"Tree-sitter indent rules.")
(defvar java-ts-mode--keywords
'("abstract" "assert" "break" "case" "catch"
"class" "continue" "default" "do" "else"
"enum" "exports" "extends" "final" "finally"
"for" "if" "implements" "import" "instanceof"
"interface" "module" "native" "new" "non-sealed"
"open" "opens" "package" "private" "protected"
"provides" "public" "requires" "return" "sealed"
"static" "strictfp" "switch" "synchronized"
"throw" "throws" "to" "transient" "transitive"
"try" "uses" "volatile" "while" "with" "record")
"Java keywords for tree-sitter font-locking.")
(defvar java-ts-mode--operators
'("+" ":" "++" "-" "--" "&" "&&" "|" "||" "="
"!=" "==" "*" "/" "%" "<" "<=" ">" ">="
"-=" "+=" "*=" "/=" "%=" "->" "^" "^="
"|=" "~" ">>" ">>>" "<<" "::" "?" "&=")
"Java operators for tree-sitter font-locking.")
(defvar java-ts-mode--font-lock-settings
(treesit-font-lock-rules
:language 'java
:override t
:feature 'comment
`((line_comment) @font-lock-comment-face
(block_comment) @font-lock-comment-face)
:language 'java
:override t
:feature 'constant
`(((identifier) @font-lock-constant-face
(:match "^[A-Z_][A-Z_\\d]*$" @font-lock-constant-face))
[(true) (false)] @font-lock-constant-face)
:language 'java
:override t
:feature 'keyword
`([,@java-ts-mode--keywords
(this)] @font-lock-keyword-face
(labeled_statement
(identifier) @font-lock-keyword-face))
:language 'java
:override t
:feature 'operator
`([,@java-ts-mode--operators] @font-lock-operator-face
"@" @font-lock-constant-face)
:language 'java
:override t
:feature 'annotation
`((annotation
name: (identifier) @font-lock-constant-face)
(marker_annotation
name: (identifier) @font-lock-constant-face))
:language 'java
:override t
:feature 'string
`((string_literal) @font-lock-string-face
(text_block) @font-lock-string-face)
:language 'java
:override t
:feature 'literal
`((null_literal) @font-lock-constant-face
(binary_integer_literal) @font-lock-number-face
(decimal_integer_literal) @font-lock-number-face
(hex_integer_literal) @font-lock-number-face
(octal_integer_literal) @font-lock-number-face
(decimal_floating_point_literal) @font-lock-number-face
(hex_floating_point_literal) @font-lock-number-face)
:language 'java
:override t
:feature 'type
'((interface_declaration
name: (identifier) @font-lock-type-face)
(class_declaration
name: (identifier) @font-lock-type-face)
(record_declaration
name: (identifier) @font-lock-type-face)
(enum_declaration
name: (identifier) @font-lock-type-face)
(constructor_declaration
name: (identifier) @font-lock-type-face)
(field_access
object: (identifier) @font-lock-type-face)
(method_reference (identifier) @font-lock-type-face)
(scoped_identifier (identifier) @font-lock-variable-name-face)
((scoped_identifier name: (identifier) @font-lock-type-face)
(:match "^[A-Z]" @font-lock-type-face))
(type_identifier) @font-lock-type-face
[(boolean_type)
(integral_type)
(floating_point_type)
(void_type)] @font-lock-type-face)
:language 'java
:override t
:feature 'definition
`((method_declaration
name: (identifier) @font-lock-function-name-face)
(variable_declarator
name: (identifier) @font-lock-variable-name-face)
(element_value_pair
key: (identifier) @font-lock-property-face)
(formal_parameter
name: (identifier) @font-lock-variable-name-face)
(catch_formal_parameter
name: (identifier) @font-lock-variable-name-face))
:language 'java
:override t
:feature 'expression
'((method_invocation
object: (identifier) @font-lock-variable-name-face)
(method_invocation
name: (identifier) @font-lock-function-name-face)
(argument_list (identifier) @font-lock-variable-name-face))
:language 'java
:feature 'bracket
'((["(" ")" "[" "]" "{" "}"]) @font-lock-bracket-face)
:language 'java
:feature 'delimiter
'((["," ":" ";"]) @font-lock-delimiter-face))
"Tree-sitter font-lock settings for `java-ts-mode'.")
(defun java-ts-mode--imenu-1 (node)
"Helper for `java-ts-mode--imenu'.
Find string representation for NODE and set marker, then recurse
the subtrees."
(let* ((ts-node (car node))
(subtrees (mapcan #'java-ts-mode--imenu-1 (cdr node)))
(name (when ts-node
(or (treesit-node-text
(or (treesit-node-child-by-field-name
ts-node "name"))
t)
"Unnamed node")))
(marker (when ts-node
(set-marker (make-marker)
(treesit-node-start ts-node)))))
(cond
((null ts-node) subtrees)
(subtrees
`((,name ,(cons name marker) ,@subtrees)))
(t
`((,name . ,marker))))))
(defun java-ts-mode--imenu ()
"Return Imenu alist for the current buffer."
(let* ((node (treesit-buffer-root-node))
(class-tree (treesit-induce-sparse-tree
node "^class_declaration$" nil 1000))
(interface-tree (treesit-induce-sparse-tree
node "^interface_declaration$" nil 1000))
(enum-tree (treesit-induce-sparse-tree
node "^enum_declaration$" nil 1000))
(record-tree (treesit-induce-sparse-tree
node "^record_declaration$" nil 1000))
(method-tree (treesit-induce-sparse-tree
node "^method_declaration$" nil 1000))
(class-index (java-ts-mode--imenu-1 class-tree))
(interface-index (java-ts-mode--imenu-1 interface-tree))
(enum-index (java-ts-mode--imenu-1 enum-tree))
(record-index (java-ts-mode--imenu-1 record-tree))
(method-index (java-ts-mode--imenu-1 method-tree)))
(append
(when class-index `(("Class" . ,class-index)))
(when interface-index `(("Interface" . ,interface-index)))
(when enum-index `(("Enum" . ,enum-index)))
(when record-index `(("Record" . ,record-index)))
(when method-index `(("Method" . ,method-index))))))
;;;###autoload
(define-derived-mode java-ts-mode prog-mode "Java"
"Major mode for editing Java, powered by tree-sitter."
:group 'java
:syntax-table java-ts-mode--syntax-table
(unless (treesit-ready-p 'java)
(error "Tree-sitter for Java isn't available"))
(treesit-parser-create 'java)
;; Comments.
(setq-local comment-start "// ")
(setq-local comment-end "")
(setq-local comment-start-skip (rx (or (seq "/" (+ "/"))
(seq "/" (+ "*")))
(* (syntax whitespace))))
(setq-local comment-end-skip
(rx (* (syntax whitespace))
(group (or (syntax comment-end)
(seq (+ "*") "/")))))
;; Indent.
(setq-local treesit-simple-indent-rules java-ts-mode--indent-rules)
;; Electric
(setq-local electric-indent-chars
(append "{}():;," electric-indent-chars))
;; Navigation.
(setq-local treesit-defun-type-regexp
(regexp-opt '("method_declaration"
"class_declaration"
"record_declaration"
"interface_declaration"
"enum_declaration"
"import_declaration"
"package_declaration"
"module_declaration")))
;; Font-lock.
(setq-local treesit-font-lock-settings java-ts-mode--font-lock-settings)
(setq-local treesit-font-lock-feature-list
'(( comment definition )
( constant keyword string type)
( annotation expression literal)
( bracket delimiter operator)))
;; Imenu.
(setq-local imenu-create-index-function #'java-ts-mode--imenu)
(setq-local which-func-functions nil) ;; Piggyback on imenu
(treesit-major-mode-setup))
(provide 'java-ts-mode)
;;; java-ts-mode.el ends here