textDocument/hover 混合 textDocument/signatureHelp

Emacs-general
1

有兩個輔助閱讀程式碼的LSP功能

textDocument/hover

  • lsp-mode自帶lsp--on-hover，用eldoc-documentation-function渲染
  • 若開啓lsp-ui-doc，eldoc-documentation-function會被修改爲lsp-ui-doc--eldoc，可以同時顯示在echo area和child frame，見下圖
  • eglot, eldoc

scree
scree848×748 370 KB

textDocument/signatureHelp

這個少有人知道是因爲lsp-mode中它並非默認lsp-hover-text-function。可以用(setq lsp-hover-text-function #'lsp--text-document-signature-help)感受在各大lang server裏什麼效果。

輔助補全，提示有哪些overloads可用，以及active parameter，見下圖

sig
sig908×708 400 KB

在evil的normal-state時，可以始終使用textDocument/hover。而在insert-state且point被非匹配的(包裹，則應該用textDocument/signatureHelp。這個lsp-mode PR能高亮eldoc中的active parameter。

如何實現這個邏輯呢？

(defun +my/lsp-ui-doc--eldoc (&rest _)
  (when (and (lsp--capability "documentHighlightProvider")
             lsp-highlight-symbol-at-point)
    (lsp-symbol-highlight))
  (if (evil-insert-state-p)
      (lsp--text-document-signature-help)
      lsp-ui-doc--string-eldoc
      ))

(advice-add #'lsp-ui-doc--eldoc :override #'+my/lsp-ui-doc--eldoc)

目前lsp-mode的signatureHelp實現的缺陷是檢測(symbol-at-point)，但對於：foo(<point> foo(a, <point>等位置(symbol-at-point)爲nil，而用戶也期望在這些位置獲得signatureHelp。

另外也要注意不要讓eldoc頻繁出現消失，閃爍會造成不好的使用者經驗。

https://github.com/emacs-lsp/lsp-mode/blob/signature-help/lsp-methods.el#L1715

把這個改得好一點(考慮下其他語言的language server)，我可以merge到lsp-ui (不太懂elisp但是恰好有權力~~)

註，今天把textDocument/signatureHelp重寫爲clangd式樣了，但沒有用他們的index輔助啓發(我沒有強需求加signal)

ccls的textDocument/hover用於liblmdb/mdb.c(10000+行)有<2ms延遲。粗糙測試，cache能把0.8ms 1.1ms降低到0.4~0.6ms。 clangd有10~20ms，但實時（無需保存）。因爲每次請求都會構造clang CompilerInvocation並parse，但這個開銷低於我的預期

這些區別是無關緊要的，因爲他們足夠快了。主要時間花在Emacs端UI展示上。

另外忘記提現在預設completion.detailedLabel: true，irony式樣的補全(label爲具體的foo(int a) -> int而非僅僅foo)

另外有個completion/duplicateOptional，開啓的話(預設)，int foo(int a, int b = 3)會顯示爲兩個補全項：

  • foo(int a) -> int
  • foo(int a, int b = 3) -> int
2 个赞
2

好强大 可惜我不会

3

在foo(par<point>am1, param2)旁移動

觸發鏈：

  • eldoc-documentation-function
  • lsp--on-hover or advised lsp-ui-doc--eldoc
  • lsp--text-document-signature-help
  • lsp--make-text-document-signature-help-callback
  • eldoc-message 相同內容也會在echo area闪烁。感覺不舒服
4

lsp 的体验还需改进，有时候 hover 呼啦占据一大片，光标所在上下文被遮住，反而造成干扰，不知道是不是因为终端的关系。

想起以前用过的盗版 Source Insight，它固定一个小窗口显示定义／文档信息，必要时双击可以把小窗口替换到主窗口，读代码跳转非常方便：

app-wide-2.jpeg1251×833 169 KB

Emacs 如果不用鼠标，恐怕很难复制这种体验。小窗口如果不用鼠标滚屏，显示不了多少信息，快捷键跳过去翻页又略显麻烦，除非 scroll-other-window。另外 Emacs 窗口没有主次之分，很容易被 kill 掉。

5

我目前的做法就是(setq lsp-ui-doc-position 'at-point) 加一个toggle-lsp-ui-mode的函数绑定到s-j or C-j，这样就跟vscode/intellij差不多了

6

(setq lsp-ui-doc-position 'at-point)會遮擋右下方文字，也不太方便……你們有精力看看怎麼判斷lsp-ui-doc是否會遮擋point，改進下？

7

emm，我就是用s-j toggle lsp ui childframe啊。然后我启动默认的就是hide的，这样就不会有遮挡问题了啊。

(defun toggle-lsp-ui-doc ()
  (interactive)
  (if lsp-ui-doc-mode
      (progn
        (lsp-ui-doc-mode -1)
        (lsp-ui-doc--hide-frame))
    (lsp-ui-doc-mode 1))
  (setq-local eldoc-documentation-function 'ignore))

(defun my-lsp-mode-hook ()
  ;; disable lsp-highlight-symbol
  ;; (setq lsp-highlight-symbol-at-point nil)

  ;; toggle off lsp-ui-doc by default
  (toggle-lsp-ui-doc)

  ;; overwrite s-j key for toggle-lsp-ui-doc
  (global-set-key (kbd "s-j") #'toggle-lsp-ui-doc))
(add-hook 'lsp-mode-hook #'my-lsp-mode-hook)
1 个赞
8

我覺得一個臨時隱藏childframe的功能就足夠了。

但現在(lsp-ui-doc--hide-frame)不夠，還會繼續popup，原因可能是：

; lsp-ui-doc.el
      (add-hook 'post-command-hook 'lsp-ui-doc--make-request nil t)

和lsp-ui-doc--make-request實現機制有關。你看下這個怎麼改進？

9

在ubuntu 16.04上编译失败了，说不支持c++17

CC=gcc-8 CXX=g++-8 cmake . -DCMAKE_CXX_FLAGS="-std=c++17"

man g++-8是有这个选项的

当然，默认是gcc-5，这个不支持。

还有用AUR的ccls的话，项目根目录放一个.ccls-root(我设置了eglot识别这个文件)，传递fileInfo的时候总说找不到这个文件(应该是clang里的CompilationDatabase类没有，不知道ccls是不是用的这个)。

10

裝gcc 7或8

Create new page · MaskRay/ccls Wiki · GitHub

  • On Linux, building requires libstdc++ shipped with GCC > 7.0 for C++17 header files, even if you use clang++.

$ccls/fileInfo

(defun ccls-file-info ()
  (lsp--cur-workspace-check)
  (lsp--send-request
   (lsp--make-request "$ccls/fileInfo"
                      `(:textDocument ,(lsp--text-document-identifier)))))

要看eglot怎麼構造custom request

.ccls-root是我用來標識project root的方式，當我不想用.projectile時。compiler options通過.ccls或compile_commands.json傳遞。

11

libstdc++-8-dev这个是装了的，编译器设置的g++-8的话(如上)，库会链接正确的吧，不过cmake还是说不支持。

eglot的话，下面的方法是没问题的，不过他们8月份把一个地方改了，我回滚到前一个commit就没问题了，我看ccls应该没改这里。

12

判斷libstdc++-8-dev是否被用：

g++ -v -E -xc++ /dev/null
clang++ -v -E -xc++ /dev/null

觀察#include <...> search starts here:

-DCMAKE_CXX_COMPILER=clang++可能比CXX=clang++好。

13

临时隐藏可能不够。vscode之类的鼠标用户是可以通过hover来显示，emacs下大家用鼠标比较少，缺少了鼠标的事件，只能通过按键来toggle吧，把lsp-ui-doc-mode关闭/开启这样子。这样也不会再触发lsp-ui-doc—make-request了吧

14

cmake . -DCMAKE_CXX_COMPILER=g++-8还是不行，头文件(g++-8 -E -v -xc++ - < /dev/null)：

 /usr/include/c++/8                                                                                                     
 /usr/include/x86_64-linux-gnu/c++/8                                                                                    
 /usr/include/c++/8/backward                                                                                            
 /usr/lib/gcc/x86_64-linux-gnu/8/include                                                                                
 /usr/local/include                                                                                                     
 /usr/lib/gcc/x86_64-linux-gnu/8/include-fixed                                                                          
 /usr/include/x86_64-linux-gnu                                                                                          
 /usr/include
15

閱讀Release/CMakeFiles/CMakeOutput.log，假設構建目錄是Release (即 cmake -H. -BRelease中的Release)

你說“不行”兩字，資訊量很低。

16

主要是它报的错直接是编译器不支持C++17

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Detecting CXX [-std=c++14] compiler features compiled with the following output:
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Detecting CXX [-std=c++11] compiler features compiled with the following output:
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cmake 3.8起支援CXX_STANDARD C++17