/
go-mode.el
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go-mode.el
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;;; go-mode.el --- Major mode for the Go programming language
;;; Commentary:
;; Copyright 2013 The go-mode Authors. All rights reserved.
;; Use of this source code is governed by a BSD-style
;; license that can be found in the LICENSE file.
;; Author: The go-mode Authors
;; Version: 1.6.0
;; Keywords: languages go
;; Package-Requires: ((emacs "26.1"))
;; URL: https://github.com/dominikh/go-mode.el
;;
;; This file is not part of GNU Emacs.
;;; Code:
(require 'cl-lib)
(require 'compile)
(require 'etags)
(require 'ffap)
(require 'find-file)
(require 'ring)
(require 'url)
(require 'xref)
(eval-when-compile
(defmacro go--forward-word (&optional arg)
(if (fboundp 'forward-word-strictly)
`(forward-word-strictly ,arg)
`(forward-word ,arg))))
(defun go--delete-whole-line (&optional arg)
"Delete the current line without putting it in the `kill-ring'.
Derived from function `kill-whole-line'. ARG is defined as for that
function."
(setq arg (or arg 1))
(if (and (> arg 0)
(eobp)
(save-excursion (forward-visible-line 0) (eobp)))
(signal 'end-of-buffer nil))
(if (and (< arg 0)
(bobp)
(save-excursion (end-of-visible-line) (bobp)))
(signal 'beginning-of-buffer nil))
(cond ((zerop arg)
(delete-region (progn (forward-visible-line 0) (point))
(progn (end-of-visible-line) (point))))
((< arg 0)
(delete-region (progn (end-of-visible-line) (point))
(progn (forward-visible-line (1+ arg))
(unless (bobp)
(backward-char))
(point))))
(t
(delete-region (progn (forward-visible-line 0) (point))
(progn (forward-visible-line arg) (point))))))
(defun go-goto-opening-parenthesis (&optional _legacy-unused)
"Move up one level of parentheses.
Return non-nil if there was a paren to move up to."
;; The old implementation of go-goto-opening-parenthesis had an
;; optional argument to speed up the function. It didn't change the
;; function's outcome.
;; Silently fail if there's no matching opening parenthesis.
(let ((open-char (nth 1 (syntax-ppss))))
(when open-char
(goto-char open-char))))
(defconst go-dangling-operators-regexp "[^-]-\\|[^+]\\+\\|[/*&><.=|^]")
(defconst go--max-dangling-operator-length 2
"The maximum length of dangling operators.
This must be at least the length of the longest string matched by
‘go-dangling-operators-regexp’ and must be updated whenever that
constant is changed.")
(defconst go-identifier-regexp "[[:word:][:multibyte:]]+")
(defconst go-type-name-no-prefix-regexp "\\(?:[[:word:][:multibyte:]]+\\.\\)?[[:word:][:multibyte:]]+")
(defconst go-qualified-identifier-regexp (concat go-identifier-regexp "\\." go-identifier-regexp))
(defconst go-label-regexp go-identifier-regexp)
(defconst go-type-regexp "[[:word:][:multibyte:]*]+")
(defconst go-func-regexp (concat "\\_<func\\_>\\s *\\(" go-identifier-regexp "\\)"))
(defconst go-func-meth-regexp (concat
"\\_<func\\_>\\s *\\(?:(\\s *"
"\\(" go-identifier-regexp "\\s +\\)?" go-type-regexp
"\\s *)\\s *\\)?\\("
go-identifier-regexp
"\\)("))
(defconst go--comment-start-regexp "[[:space:]]*\\(?:/[/*]\\)")
(defconst go--case-regexp "\\([[:space:]]*case\\([[:space:]]\\|$\\)\\)")
(defconst go--case-or-default-regexp (concat "\\(" go--case-regexp "\\|" "[[:space:]]*default:\\)"))
(defconst go-builtins
'("append" "cap" "clear" "close" "complex"
"copy" "delete" "imag" "len" "make"
"max" "min" "new" "panic" "print"
"println" "real" "recover")
"All built-in functions in the Go language. Used for font locking.")
(defconst go-mode-keywords
'("break" "default" "func" "interface" "select"
"case" "defer" "go" "map" "struct"
"chan" "else" "goto" "package" "switch"
"const" "fallthrough" "if" "range" "type"
"continue" "for" "import" "return" "var")
"All keywords in the Go language. Used for font locking.")
(defconst go-constants '("nil" "true" "false" "iota"))
(defconst go-type-name-regexp (concat "\\**\\(\\(?:" go-identifier-regexp "\\.\\)?" go-identifier-regexp "\\)"))
(defvar go-dangling-cache)
(defvar go-godoc-history nil)
(defvar go--coverage-current-file-name)
(defgroup go nil
"Major mode for editing Go code."
:link '(url-link "https://github.com/dominikh/go-mode.el")
:group 'languages)
(defgroup go-cover nil
"Options specific to `cover`."
:group 'go)
(defgroup godoc nil
"Options specific to `godoc'."
:group 'go)
(defcustom go-fontify-function-calls t
"Fontify function and method calls if this is non-nil."
:type 'boolean
:group 'go)
(defcustom go-fontify-variables t
"Fontify variable declarations if this is non-nil."
:type 'boolean
:group 'go)
(defcustom go-mode-hook nil
"Hook called by `go-mode'."
:type 'hook
:group 'go)
(defcustom go-command "go"
"The 'go' command.
Some users have multiple Go development trees and invoke the 'go'
tool via a wrapper that sets GOROOT and GOPATH based on the
current directory. Such users should customize this variable to
point to the wrapper script."
:type 'string
:group 'go)
(defcustom gofmt-command "gofmt"
"The 'gofmt' command.
Some users may replace this with 'goimports'
from https://golang.org/x/tools/cmd/goimports."
:type 'string
:group 'go)
(defcustom gofmt-args nil
"Additional arguments to pass to gofmt."
:type '(repeat string)
:group 'go)
(defcustom gofmt-show-errors 'buffer
"Where to display gofmt error output.
It can either be displayed in its own buffer, in the echo area, or not at all.
Please note that Emacs outputs to the echo area when writing
files and will overwrite gofmt's echo output if used from inside
a `before-save-hook'."
:type '(choice
(const :tag "Own buffer" buffer)
(const :tag "Echo area" echo)
(const :tag "None" nil))
:group 'go)
(defcustom godef-command "godef"
"The 'godef' command."
:type 'string
:group 'go)
(defcustom go-other-file-alist
'(("_test\\.go\\'" (".go"))
("\\.go\\'" ("_test.go")))
"See the documentation of `ff-other-file-alist' for details."
:type '(repeat (list regexp (choice (repeat string) function)))
:group 'go)
(defcustom go-packages-function 'go-packages-go-list
"Function called by `go-packages' to determine the list of available packages.
This is used in e.g. tab completion in `go-import-add'.
This package provides two functions: `go-packages-go-list' uses
'go list all' to determine all Go packages. `go-packages-native' uses
elisp to find all .a files in all /pkg/ directories.
`go-packages-native' is obsolete as it doesn't behave correctly with
the Go build cache or Go modules."
:type 'function
:package-version '(go-mode . 1.4.0)
:group 'go)
(defcustom go-guess-gopath-functions (list #'go-plain-gopath)
"Functions to call in sequence to detect a project's GOPATH.
The functions in this list will be called one after another,
until a function returns non-nil. The order of the functions in
this list is important, as some project layouts may superficially
look like others."
:type '(repeat function)
:group 'go)
(make-obsolete-variable 'go-guess-gopath-functions "GOPATH has been deprecated in favour of Go modules." "1.7.0")
(defcustom go-confirm-playground-uploads t
"Ask before uploading code to the public Go Playground.
Set this to nil to upload without prompting."
:type 'boolean
:group 'go)
(defcustom godoc-command "go doc"
"Which executable to use for `godoc'.
This can be either an absolute path or an executable in PATH."
:type 'string
:group 'go)
(defcustom godoc-and-godef-command "go doc"
"Which executable to use for `godoc-and-godef'.
This can be either an absolute path or an executable in PATH."
:type 'string
:group 'go)
(defcustom godoc-use-completing-read nil
"Provide auto-completion for godoc.
Only really desirable when using `godoc' instead of `go doc'."
:type 'boolean
:group 'godoc)
(defcustom godoc-reuse-buffer nil
"Reuse a single *godoc* buffer to display godoc-at-point calls.
The default behavior is to open a separate buffer for each call."
:type 'boolean
:group 'godoc)
(defcustom godoc-at-point-function #'godoc-and-godef
"Function to call to display the documentation for an
identifier at a given position.
This package provides two functions: `godoc-and-godef' uses a
combination of godef and godoc to find the documentation. This
approach has several caveats. See its documentation for more
information. The second function, `godoc-gogetdoc' uses an
additional tool that correctly determines the documentation for
any identifier. It provides better results than
`godoc-and-godef'."
:type 'function
:group 'godoc)
(defun godoc-and-godef (point)
"Use a combination of godef and godoc to guess the documentation at POINT.
Due to a limitation in godoc, it is not possible to differentiate
between functions and methods, which may cause `godoc-at-point'
to display more documentation than desired. Furthermore, it
doesn't work on package names or variables.
Consider using ‘godoc-gogetdoc’ instead for more accurate results."
(condition-case nil
(let* ((output (godef--call point))
(file (car output))
(name-parts (split-string (cadr output) " "))
(first (car name-parts)))
(if (not (godef--successful-p file))
(message "%s" (godef--error file))
(go--godoc (format "%s %s"
(file-name-directory file)
(if (or (string= first "type") (string= first "const"))
(cadr name-parts)
(car name-parts)))
godoc-and-godef-command)))
(file-error (message "Could not run godef binary"))))
(defun godoc-gogetdoc (point)
"Use the gogetdoc tool to find the documentation for an identifier at POINT.
You can install gogetdoc with 'go get -u github.com/zmb3/gogetdoc'."
(if (not (buffer-file-name (go--coverage-origin-buffer)))
;; TODO: gogetdoc supports unsaved files, but not introducing
;; new artificial files, so this limitation will stay for now.
(error "Cannot use gogetdoc on a buffer without a file name"))
(let ((posn (format "%s:#%d" (file-truename buffer-file-name) (1- (position-bytes point))))
(out (godoc--get-buffer "<at point>")))
(with-temp-buffer
(go--insert-modified-files)
(call-process-region (point-min) (point-max) "gogetdoc" nil out nil
"-modified"
(format "-pos=%s" posn)))
(with-current-buffer out
(goto-char (point-min))
(godoc-mode)
(display-buffer (current-buffer) t))))
(defun go--kill-new-message (url)
"Make URL the latest kill and print a message."
(kill-new url)
(message "%s" url))
(defcustom go-play-browse-function 'go--kill-new-message
"Function to call with the Playground URL.
See `go-play-region' for more details."
:type '(choice
(const :tag "Nothing" nil)
(const :tag "Kill + Message" go--kill-new-message)
(const :tag "Browse URL" browse-url)
(function :tag "Call function"))
:group 'go)
(defcustom go-coverage-display-buffer-func 'display-buffer-reuse-window
"How `go-coverage' should display the coverage buffer.
See `display-buffer' for a list of possible functions."
:type 'function
:group 'go-cover)
(defface go-coverage-untracked
'((t (:foreground "#505050")))
"Coverage color of untracked code."
:group 'go-cover)
(defface go-coverage-0
'((t (:foreground "#c00000")))
"Coverage color for uncovered code."
:group 'go-cover)
(defface go-coverage-1
'((t (:foreground "#808080")))
"Coverage color for covered code with weight 1."
:group 'go-cover)
(defface go-coverage-2
'((t (:foreground "#748c83")))
"Coverage color for covered code with weight 2."
:group 'go-cover)
(defface go-coverage-3
'((t (:foreground "#689886")))
"Coverage color for covered code with weight 3."
:group 'go-cover)
(defface go-coverage-4
'((t (:foreground "#5ca489")))
"Coverage color for covered code with weight 4."
:group 'go-cover)
(defface go-coverage-5
'((t (:foreground "#50b08c")))
"Coverage color for covered code with weight 5."
:group 'go-cover)
(defface go-coverage-6
'((t (:foreground "#44bc8f")))
"Coverage color for covered code with weight 6."
:group 'go-cover)
(defface go-coverage-7
'((t (:foreground "#38c892")))
"Coverage color for covered code with weight 7."
:group 'go-cover)
(defface go-coverage-8
'((t (:foreground "#2cd495")))
"Coverage color for covered code with weight 8.
For mode=set, all covered lines will have this weight."
:group 'go-cover)
(defface go-coverage-9
'((t (:foreground "#20e098")))
"Coverage color for covered code with weight 9."
:group 'go-cover)
(defface go-coverage-10
'((t (:foreground "#14ec9b")))
"Coverage color for covered code with weight 10."
:group 'go-cover)
(defface go-coverage-covered
'((t (:foreground "#2cd495")))
"Coverage color of covered code."
:group 'go-cover)
(defvar go-mode-syntax-table
(let ((st (make-syntax-table)))
(modify-syntax-entry ?+ "." st)
(modify-syntax-entry ?- "." st)
(modify-syntax-entry ?% "." st)
(modify-syntax-entry ?& "." st)
(modify-syntax-entry ?| "." st)
(modify-syntax-entry ?^ "." st)
(modify-syntax-entry ?! "." st)
(modify-syntax-entry ?= "." st)
(modify-syntax-entry ?< "." st)
(modify-syntax-entry ?> "." st)
(modify-syntax-entry ?/ ". 124b" st)
(modify-syntax-entry ?* ". 23" st)
(modify-syntax-entry ?\n "> b" st)
(modify-syntax-entry ?\" "\"" st)
(modify-syntax-entry ?\' "\"" st)
(modify-syntax-entry ?` "\"" st)
(modify-syntax-entry ?\\ "\\" st)
;; TODO make _ a symbol constituent now that xemacs is gone
(modify-syntax-entry ?_ "w" st)
st)
"Syntax table for Go mode.")
(defun go--fontify-type-switch-case-pre ()
"Move point to line following the end of case statement.
This is used as an anchored font lock keyword PRE-MATCH-FORM. We
expand the font lock region to include multiline type switch case
statements."
(save-excursion
(beginning-of-line)
(while (or (looking-at "[[:space:]]*\\($\\|//\\)") (go--line-suffix-p ","))
(forward-line))
(when (go--line-suffix-p ":")
(forward-line))
(point)))
(defun go--build-font-lock-keywords ()
;; we cannot use 'symbols in regexp-opt because GNU Emacs <24
;; doesn't understand that
(append
`(
;; Match param lists in func signatures. This uses the
;; MATCH-ANCHORED format (see `font-lock-keywords' docs).
;;
;; Parent/anchor match. It matches the param list opening "(".
(go--match-param-start
;; Sub-matcher that matches individual params in the param list.
(go--fontify-param
;; Pre-match form that runs before the first sub-match.
(go--fontify-param-pre)
;; Post-match form that runs after last sub-match.
(go--fontify-param-post)
;; Subexp 1 is the param variable name, if any.
(1 font-lock-variable-name-face nil t)
;; Subexp 2 is the param type name, if any. We set the LAXMATCH
;; flag to allow optional regex groups.
(2 font-lock-type-face nil t)))
;; Special case to match non-parenthesized function results. For
;; example, "func(i int) string".
(go--match-single-func-result 1 font-lock-type-face)
;; Match name+type pairs, such as "foo bar" in "var foo bar".
(go--match-ident-type-pair 2 font-lock-type-face)
;; An anchored matcher for type switch case clauses.
(go--match-type-switch-case
(go--fontify-type-switch-case
(go--fontify-type-switch-case-pre)
nil
(1 font-lock-type-face)))
;; Match variable names in var decls, constant names in const
;; decls, and type names in type decls.
(go--match-decl
(1 font-lock-variable-name-face nil t)
(2 font-lock-constant-face nil t)
(3 font-lock-type-face nil t))
(,(concat "\\_<" (regexp-opt go-mode-keywords t) "\\_>") . font-lock-keyword-face)
(,(concat "\\(\\_<" (regexp-opt go-builtins t) "\\_>\\)[[:space:]]*(") 1 font-lock-builtin-face)
(,(concat "\\_<" (regexp-opt go-constants t) "\\_>") . font-lock-constant-face)
;; Function (not method) name
(,go-func-regexp 1 font-lock-function-name-face))
(if go-fontify-function-calls
;; Function call/method name
`((,(concat "\\(" go-identifier-regexp "\\)[[:space:]]*(") 1 font-lock-function-name-face)
;; Bracketed function call
(,(concat "[^[:word:][:multibyte:]](\\(" go-identifier-regexp "\\))[[:space:]]*(") 1 font-lock-function-name-face))
;; Method name
`((,go-func-meth-regexp 2 font-lock-function-name-face)))
`(
;; Raw string literal, needed for font-lock-syntactic-keywords
("\\(`[^`]*`\\)" 1 font-lock-multiline)
;; RHS of type alias.
(go--match-type-alias 2 font-lock-type-face)
;; Arrays/slices: []<type> | [123]<type> | [some.Const]<type> | [someConst]<type> | [...]<type>
(,(concat "\\(?:^\\|[^[:word:][:multibyte:]]\\)\\[\\(?:[[:digit:]]+\\|" go-qualified-identifier-regexp "\\|" go-identifier-regexp "\\|\\.\\.\\.\\)?\\]" go-type-name-regexp) 1 font-lock-type-face)
;; Unary "!"
("\\(!\\)[^=]" 1 font-lock-negation-char-face)
;; Composite literal type
(,(concat go-type-name-regexp "{") 1 font-lock-type-face)
;; Map value type
(go--match-map-value 1 font-lock-type-face)
;; Map key type
(,(concat "\\_<map\\_>\\[" go-type-name-regexp) 1 font-lock-type-face)
;; Channel type
(,(concat "\\_<chan\\_>[[:space:]]*\\(?:<-[[:space:]]*\\)?" go-type-name-regexp) 1 font-lock-type-face)
;; "new()"/"make()" type
(,(concat "\\_<\\(?:new\\|make\\)\\_>\\(?:[[:space:]]\\|)\\)*(" go-type-name-regexp) 1 font-lock-type-face)
;; Type assertion
(,(concat "\\.\\s *(" go-type-name-regexp) 1 font-lock-type-face)
;; Composite literal field names and label definitions.
(go--match-ident-colon 1 font-lock-constant-face)
;; Labels in goto/break/continue
(,(concat "\\_<\\(?:goto\\|break\\|continue\\)\\_>[[:space:]]*\\(" go-label-regexp "\\)") 1 font-lock-constant-face))))
(let ((m (define-prefix-command 'go-goto-map)))
(define-key m "a" #'go-goto-arguments)
(define-key m "d" #'go-goto-docstring)
(define-key m "f" #'go-goto-function)
(define-key m "i" #'go-goto-imports)
(define-key m "m" #'go-goto-method-receiver)
(define-key m "n" #'go-goto-function-name)
(define-key m "r" #'go-goto-return-values))
(defvar go-mode-map
(let ((m (make-sparse-keymap)))
(unless (boundp 'electric-indent-chars)
(define-key m "}" #'go-mode-insert-and-indent)
(define-key m ")" #'go-mode-insert-and-indent))
(define-key m (kbd "C-c C-a") #'go-import-add)
(define-key m (kbd "C-c C-j") #'godef-jump)
(define-key m (kbd "C-x 4 C-c C-j") #'godef-jump-other-window)
(define-key m (kbd "C-c C-d") #'godef-describe)
(define-key m (kbd "C-c C-f") 'go-goto-map)
m)
"Keymap used by ‘go-mode’.")
(easy-menu-define go-mode-menu go-mode-map
"Menu for Go mode."
'("Go"
["Describe Expression" godef-describe t]
["Jump to Definition" godef-jump t]
"---"
["Add Import" go-import-add t]
["Go to Imports" go-goto-imports t]
"---"
("Playground"
["Send Buffer" go-play-buffer t]
["Send Region" go-play-region t]
["Download" go-download-play t])
"---"
["Coverage" go-coverage t]
["Gofmt" gofmt t]
["Godoc" godoc t]
"---"
["Customize Mode" (customize-group 'go) t]))
(defun go-mode-insert-and-indent (key)
"Invoke the global binding of KEY, then reindent the line."
(interactive (list (this-command-keys)))
(call-interactively (lookup-key (current-global-map) key))
(indent-according-to-mode))
(defmacro go-paren-level ()
`(car (syntax-ppss)))
(defmacro go-in-string-or-comment-p ()
`(nth 8 (syntax-ppss)))
(defmacro go-in-string-p ()
`(nth 3 (syntax-ppss)))
(defmacro go-in-comment-p ()
`(nth 4 (syntax-ppss)))
(defmacro go-goto-beginning-of-string-or-comment ()
`(goto-char (nth 8 (syntax-ppss))))
(defun go--backward-irrelevant (&optional stop-at-string)
"Skip backwards over any characters that are irrelevant for
indentation and related tasks.
It skips over whitespace, comments, cases and labels and, if
STOP-AT-STRING is not true, over strings."
(let (pos (start-pos (point)))
(skip-chars-backward "\n\s\t")
(if (and (save-excursion (beginning-of-line) (go-in-string-p))
(= (char-before) ?`)
(not stop-at-string))
(backward-char))
(if (and (go-in-string-p)
(not stop-at-string))
(go-goto-beginning-of-string-or-comment))
(if (looking-back "\\*/" (line-beginning-position))
(backward-char))
(if (go-in-comment-p)
(go-goto-beginning-of-string-or-comment))
(setq pos (point))
(beginning-of-line)
(if (or (looking-at (concat "^" go-label-regexp ":"))
(looking-at "^[[:space:]]*\\(case .+\\|default\\):"))
(end-of-line 0)
(goto-char pos))
(if (/= start-pos (point))
(go--backward-irrelevant stop-at-string))
(/= start-pos (point))))
(defun go--buffer-narrowed-p ()
"Return non-nil if the current buffer is narrowed."
(/= (buffer-size)
(- (point-max)
(point-min))))
(defun go-previous-line-has-dangling-op-p ()
"Return non-nil if the current line is a continuation line.
The return value is cached based on the current `line-beginning-position'."
(let* ((line-begin (line-beginning-position))
(val (gethash line-begin go-dangling-cache 'nope)))
(when (or (go--buffer-narrowed-p) (equal val 'nope))
(save-excursion
(go--forward-line -1)
(if (go--current-line-has-dangling-op-p)
(setq val (line-end-position))
(setq val nil))
(if (not (go--buffer-narrowed-p))
(puthash line-begin val go-dangling-cache))))
val))
(defun go--current-line-has-dangling-op-p ()
"Return non-nil if current line ends in a dangling operator.
The return value is not cached."
(or
(and
(go--line-suffix-p go-dangling-operators-regexp)
;; "=" does not behave like a dangling operator in decl statements.
(not (go--line-suffix-p "\\(?:var\\|type\\|const\\)[[:space:]].*="))
;; Don't mistake "1234." for a dangling operator.
(not (go--line-suffix-p "[[:space:]]-?[[:digit:]][_0-9]*\\.")))
;; treat comma as dangling operator in certain cases
(and
(go--line-suffix-p ",")
(save-excursion (end-of-line) (go--commas-indent-p)))))
(defun go--commas-indent-p ()
"Return non-nil if in a context where dangling commas indent next line."
(not (or
(go--open-paren-position)
(go--in-composite-literal-p)
(go--in-case-clause-list-p)
(go--in-struct-definition-p))))
(defun go--in-case-clause-list-p ()
"Return non-nil if inside a multi-line case cause list.
This function is only concerned with list items on lines after the
case keyword. It returns nil for the case line itself."
(save-excursion
(beginning-of-line)
(when (not (looking-at go--case-or-default-regexp))
(let (saw-colon)
;; optionally skip line with the colon
(when (go--line-suffix-p ":")
(setq saw-colon t)
(forward-line -1))
;; go backwards while at a comment or a line ending in comma
(while (and
(or
(go--boring-line-p)
(go--line-suffix-p ","))
(not (looking-at go--case-regexp))
(go--forward-line -1)))
(and
(looking-at-p go--case-regexp)
;; we weren't in case list if first line ended in colon
;; and the "case" line ended in colon
(not (and saw-colon (looking-at ".*:[[:space:]]*$"))))))))
(defun go--in-composite-literal-p ()
"Return non-nil if point is in a composite literal."
(save-excursion
(save-match-data
(and
(go-goto-opening-parenthesis)
;; Opening paren-like character is a curly.
(eq (char-after) ?{)
(or
;; Curly is preceded by non space (e.g. "Foo{"), definitely
;; composite literal.
(zerop (skip-syntax-backward " "))
;; Curly preceded by comma or semicolon. This is a composite
;; literal with implicit type name.
(looking-back "[,:]" (1- (point)))
;; If we made it to the beginning of line we are either a naked
;; block or a composite literal with implicit type name. If we
;; are the latter, we must be contained in another composite
;; literal.
(and (bolp) (go--in-composite-literal-p)))))))
(defun go--in-paren-with-prefix-p (paren prefix)
(save-excursion
(and
(go-goto-opening-parenthesis)
(eq (char-after) paren)
(skip-syntax-backward " ")
(> (point) (length prefix))
(string= prefix (buffer-substring (- (point) (length prefix)) (point))))))
(defun go--in-struct-definition-p ()
"Return non-nil if point is inside a struct definition."
(go--in-paren-with-prefix-p ?{ "struct"))
(defun go--in-interface-p ()
"Return non-nil if point is inside an interface definition."
(go--in-paren-with-prefix-p ?{ "interface"))
(defun go--in-type-switch-p ()
"Return non-nil if point is inside a type switch statement."
(go--in-paren-with-prefix-p ?{ ".(type)"))
(defun go--open-paren-position ()
"Return non-nil if point is between '(' and ')'.
The return value is the position of the opening paren."
(save-excursion
(let ((start-paren-level (go-paren-level)))
(and
(go-goto-opening-parenthesis)
;; opening paren-like character is actually a paren
(eq (char-after) ?\()
;; point is before the closing paren
(< (go-paren-level) start-paren-level)
(point)))))
(defun go-indentation-at-point ()
"Return the appropriate indentation for the current line."
(save-excursion
(beginning-of-line)
(if (go-in-comment-p)
(go--multiline-comment-indent)
(go--indentation-at-point))))
;; It's unfortunate that the user cannot reindent the current line to
;; align with the previous line; however, if they could, then people
;; who use reindent-then-newline-and-indent wouldn't be able to
;; explicitly indent lines inside comments.
(defun go--multiline-comment-indent ()
"Return the appropriate indent inside multiline comment.
Assumes point is at beginning of line within comment. This
function has basic logic to indent as you add new lines to a
multiline comment, and to line up all the `*' if each line starts
with `*'. The gofmt behavior for multiline comments is
surprisingly complex and strange/buggy, so we just aim to do
something simple rather than encode all the subtle behavior."
(let* (;; Indent of current line.
(indent (current-indentation))
;; Indent of opening "/*".
start-indent
;; Default indent to use based on preceding context.
natural-indent
;; Non-nil means keep existing indent and give up calculating indent.
give-up
;; Whether all comment lines (except first) begin with "*".
(all-star t))
(save-excursion
(go-goto-beginning-of-string-or-comment)
(setq start-indent (current-indentation))
;; If other stuff precedes start of multiline comment, give up.
(setq give-up (/= (current-column) start-indent))
;; Skip "/*".
(forward-char 2)
(skip-syntax-forward " ")
(if (not (eolp))
;; If we aren't at EOL, we have content on the first line.
;; Base our natural indent on that.
(setq natural-indent (current-column))
;; Otherwise default to 1 space beyond "/*".
(setq natural-indent (+ start-indent 3)))
(let (done)
(while (not done)
(setq done (or (looking-at ".*\\*/") (not (zerop (forward-line)))))
(setq all-star (and all-star (looking-at "[[:space:]]*\\*"))))))
;; If previous line has comment content, use its indent as our
;; natural indent.
(save-excursion
(when (zerop (forward-line -1))
(beginning-of-line)
(when (and (go-in-comment-p) (> (current-indentation) 0))
(setq natural-indent (current-indentation)))))
(cond
(give-up indent)
(all-star (1+ start-indent))
;; Closing "*/" with no preceding content always lines up with "/*".
((looking-at "[[:space:]]*\\*/") start-indent)
;; If the line is already indented, leave it.
(t (if (zerop indent) natural-indent indent)))))
(defun go--indentation-at-point ()
"Return the appropriate indentation for the current non-comment line.
This function works by walking a line's characters backwards. When it
encounters a closing paren or brace it bounces to the corresponding
opener. If it arrives at the beginning of the line you are indenting,
it moves to the end of the previous line if the current line is a
continuation line, else it moves to the containing opening paren or
brace. If it arrives at the beginning of a line other than the line
you are indenting, it will continue to the previous dangling line if
the line you are indenting was not a continuation line, otherwise it
is done."
(save-excursion
(beginning-of-line)
(let (
;; Beginning of our starting line.
(start-line (point))
;; Whether this is our first iteration of the outer while loop.
(first t)
;; Whether we start in a block (i.e. our first line is not a
;; continuation line and is in an "if", "for", etc. block).
(in-block)
;; Our desired indent relative to our ending line's indent.
(indent 0))
;; Skip leading whitespace.
(skip-syntax-forward " ")
;; Decrement indent if the first character on the line is a closer.
(when (or (eq (char-after) ?\)) (eq (char-after) ?}))
(cl-decf indent tab-width))
(while (or
;; Always run the first iteration so we process empty lines.
first
;; Otherwise stop if we are at the start of a line.
(not (bolp)))
(setq first nil)
(cl-case (char-before)
;; We have found a closer (paren or brace).
((?\) ?})
(backward-char)
(let ((bol (line-beginning-position)))
;; Jump back to corresponding opener.
(go-goto-opening-parenthesis)
;; Here we decrement the indent if we are closing an indented
;; expression. In other words, the closer's line was indented
;; relative to the opener's line, and that indent should not
;; be inherited by our starting line.
(when (and
;; We care about dangling expressions, not child blocks.
(not in-block)
;; Opener and closer aren't on same line.
(< (point) bol)
(go-previous-line-has-dangling-op-p)
;; Opener is at same paren level as start of line (ignore sub-expressions).
(eq (go-paren-level) (save-excursion (beginning-of-line) (go-paren-level)))
;; This dangling line opened indent relative to previous dangling line.
(go--continuation-line-indents-p))
(cl-decf indent tab-width))))
;; Brackets don't affect indentation, so just skip them.
((?\])
(backward-char)))
;; Skip non-closers since we are only interested in closing parens/braces.
(skip-syntax-backward "^)" (line-beginning-position))
(when (go-in-string-or-comment-p)
(go-goto-beginning-of-string-or-comment))
;; At the beginning of the starting line.
(when (= start-line (point))
;; We are a continuation line.
(if (go-previous-line-has-dangling-op-p)
(progn
;; Presume a continuation line always gets an extra indent.
;; We reduce the indent after the loop, if necessary.
(cl-incf indent tab-width)
;; Go to the end of the dangling line.
(goto-char (go-previous-line-has-dangling-op-p)))
;; If we aren't a continuation line and we have an enclosing paren
;; or brace, jump to opener and increment our indent.
(when (go-goto-opening-parenthesis)
(setq in-block (go--flow-block-p))
(cl-incf indent tab-width))))
;; If we started in a child block we must follow dangling lines
;; until they don't dangle anymore. This is to handle cases like:
;;
;; if foo ||
;; foo &&
;; foo {
;; X
;;
;; There can be an arbitrary number of indents, so we must go back to
;; the "if" to determine the indent of "X".
(when (and in-block (bolp) (go-previous-line-has-dangling-op-p))
(goto-char (go-previous-line-has-dangling-op-p))))
;; If our ending line is a continuation line but doesn't open
;; an extra indent, reduce indent. We tentatively gave indents to all
;; dangling lines and all lines inside open parens, so here we take that
;; indent back.
;;
;; 1 + 1 +
;; ending line 1 + foo( 1 + foo(
;; starting line 1, becomes 1,
;; ) )
;;
;;
;; 1 + 1 +
;; ending line 1 + becomes 1 +
;; starting line 1 1
(when (and
(go-previous-line-has-dangling-op-p)
(not (go--continuation-line-indents-p)))
(cl-decf indent tab-width))
;; Apply our computed indent relative to the indent of the
;; ending line, or 0 if we are at the top level.
(if (and
(= 0 (go-paren-level))
(not (go-previous-line-has-dangling-op-p)))
indent
(+ indent (current-indentation))))))
(defconst go--operator-chars "*/%<>&\\^+\\-|=!,."
"Individual characters that appear in operators.
Comma and period are included because they can be dangling operators, so
they need to be considered by `go--continuation-line-indents-p'")
(defun go--operator-precedence (op)
"Go operator precedence (higher binds tighter)."
(cl-case (intern op)
(\. 7) ; "." in "foo.bar", binds tightest
(! 6)
((* / % << >> & &^) 5)
((+ - | ^) 4)
((== != < <= > >=) 3)
(&& 2)
(|| 1)
(t 0)))
(defun go--flow-block-p ()
"Return whether looking at a { that opens a control flow block.
We check for a { that is preceded by a space and is not a func
literal opening brace."
(save-excursion
(when (and
(eq (char-after) ?{)
(not (zerop (skip-syntax-backward " "))))