runtime(graphql): contribute vim-graphql to Vim core

Contribute the core of my vim-graphql project (ftplugin, indent, syntax)
to the Vim project. This replaces the basic ftplugin support that was
already in the runtime with a more complete set of filetype settings. I
can assume maintainership for all of these files.

I'll continue to maintain the higher-level embedded filetype support
separately (in vim-graphql) for now, because it's fairly complex, but we
can consider integrating that code directly into vim later.

runtime files use the MIT license.

closes: #16273

Signed-off-by: Jon Parise <jon@indelible.org>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/graphql.vim b/runtime/ftplugin/graphql.vim
index 56f6e36..1717ebf 100644
--- a/runtime/ftplugin/graphql.vim
+++ b/runtime/ftplugin/graphql.vim
@@ -1,13 +1,22 @@
 " Vim filetype plugin
 " Language:	graphql
-" Maintainer:	Riley Bruins <ribru17@gmail.com>
-" Last Change:	2024 May 18
+" Maintainer:	Jon Parise <jon@indelible.org>
+" Filenames:	*.graphql *.graphqls *.gql
+" URL:		https://github.com/jparise/vim-graphql
+" License:	MIT <https://opensource.org/license/mit>
+" Last Change:	2024 Dec 21
 
 if exists('b:did_ftplugin')
   finish
 endif
 let b:did_ftplugin = 1
 
-setl comments=:# commentstring=#\ %s
+setlocal comments=:#
+setlocal commentstring=#\ %s
+setlocal formatoptions-=t
+setlocal iskeyword+=$,@-@
+setlocal softtabstop=2
+setlocal shiftwidth=2
+setlocal expandtab
 
-let b:undo_ftplugin = 'setl com< cms<'
+let b:undo_ftplugin = 'setlocal com< cms< fo< isk< sts< sw< et<'
diff --git a/runtime/indent/graphql.vim b/runtime/indent/graphql.vim
new file mode 100644
index 0000000..dc0769b
--- /dev/null
+++ b/runtime/indent/graphql.vim
@@ -0,0 +1,92 @@
+" Vim indent file
+" Language:	graphql
+" Maintainer:	Jon Parise <jon@indelible.org>
+" Filenames:	*.graphql *.graphqls *.gql
+" URL:		https://github.com/jparise/vim-graphql
+" License:	MIT <https://opensource.org/license/mit>
+" Last Change:	2024 Dec 21
+
+" Set our local options if indentation hasn't already been set up.
+" This generally means we've been detected as the primary filetype.
+if !exists('b:did_indent')
+  setlocal autoindent
+  setlocal nocindent
+  setlocal nolisp
+  setlocal nosmartindent
+
+  setlocal indentexpr=GetGraphQLIndent()
+  setlocal indentkeys=0{,0},0),0[,0],0#,!^F,o,O
+
+  let b:did_indent = 1
+endif
+
+" If our indentation function already exists, we have nothing more to do.
+if exists('*GetGraphQLIndent')
+  finish
+endif
+
+let s:cpo_save = &cpoptions
+set cpoptions&vim
+
+" searchpair() skip expression that matches in comments and strings.
+let s:pair_skip_expr =
+  \ 'synIDattr(synID(line("."), col("."), 0), "name") =~? "comment\\|string"'
+
+" Check if the character at lnum:col is inside a string.
+function s:InString(lnum, col)
+  return synIDattr(synID(a:lnum, a:col, 1), 'name') ==# 'graphqlString'
+endfunction
+
+function GetGraphQLIndent()
+  " If this is the first non-blank line, we have nothing more to do because
+  " all of our indentation rules are based on matching against earlier lines.
+  let l:prevlnum = prevnonblank(v:lnum - 1)
+  if l:prevlnum == 0
+    return 0
+  endif
+
+  " If the previous line isn't GraphQL, assume we're part of a template
+  " string and indent this new line within it.
+  let l:stack = map(synstack(l:prevlnum, 1), "synIDattr(v:val, 'name')")
+  if get(l:stack, -1) !~# '^graphql'
+    return indent(l:prevlnum) + shiftwidth()
+  endif
+
+  let l:line = getline(v:lnum)
+
+  " If this line contains just a closing bracket, find its matching opening
+  " bracket and indent the closing bracket to match.
+  let l:col = matchend(l:line, '^\s*[]})]')
+  if l:col > 0 && !s:InString(v:lnum, l:col)
+    call cursor(v:lnum, l:col)
+
+    let l:bracket = l:line[l:col - 1]
+    if l:bracket ==# '}'
+      let l:matched = searchpair('{', '', '}', 'bW', s:pair_skip_expr)
+    elseif l:bracket ==# ']'
+      let l:matched = searchpair('\[', '', '\]', 'bW', s:pair_skip_expr)
+    elseif l:bracket ==# ')'
+      let l:matched = searchpair('(', '', ')', 'bW', s:pair_skip_expr)
+    else
+      let l:matched = -1
+    endif
+
+    return l:matched > 0 ? indent(l:matched) : virtcol('.') - 1
+  endif
+
+  " If we're inside of a multiline string, continue with the same indentation.
+  if s:InString(v:lnum, matchend(l:line, '^\s*') + 1)
+    return indent(v:lnum)
+  endif
+
+  " If the previous line ended with an opening bracket, indent this line.
+  if getline(l:prevlnum) =~# '\%(#.*\)\@<![[{(]\s*$'
+    return indent(l:prevlnum) + shiftwidth()
+  endif
+
+  " Default to the existing indentation level.
+  return indent(l:prevlnum)
+endfunction
+
+let &cpoptions = s:cpo_save
+unlet s:cpo_save
diff --git a/runtime/syntax/graphql.vim b/runtime/syntax/graphql.vim
new file mode 100644
index 0000000..01d5ca2
--- /dev/null
+++ b/runtime/syntax/graphql.vim
@@ -0,0 +1,90 @@
+" Vim syntax file
+" Language:	graphql
+" Maintainer:	Jon Parise <jon@indelible.org>
+" Filenames:	*.graphql *.graphqls *.gql
+" URL:		https://github.com/jparise/vim-graphql
+" License:	MIT <https://opensource.org/license/mit>
+" Last Change:	2024 Dec 21
+
+if !exists('main_syntax')
+  if exists('b:current_syntax')
+    finish
+  endif
+  let main_syntax = 'graphql'
+endif
+
+syn case match
+
+syn match graphqlComment    "#.*$" contains=@Spell
+
+syn match graphqlOperator   "=" display
+syn match graphqlOperator   "!" display
+syn match graphqlOperator   "|" display
+syn match graphqlOperator   "&" display
+syn match graphqlOperator   "\M..." display
+
+syn keyword graphqlBoolean  true false
+syn keyword graphqlNull     null
+syn match   graphqlNumber   "-\=\<\%(0\|[1-9]\d*\)\%(\.\d\+\)\=\%([eE][-+]\=\d\+\)\=\>" display
+syn region  graphqlString   start=+"+  skip=+\\\\\|\\"+  end=+"\|$+
+syn region  graphqlString   start=+"""+ skip=+\\"""+ end=+"""+
+
+syn keyword graphqlKeyword repeatable nextgroup=graphqlKeyword skipwhite
+syn keyword graphqlKeyword on nextgroup=graphqlType,graphqlDirectiveLocation skipwhite
+
+syn keyword graphqlStructure enum scalar type union nextgroup=graphqlType skipwhite
+syn keyword graphqlStructure input interface subscription nextgroup=graphqlType skipwhite
+syn keyword graphqlStructure implements nextgroup=graphqlType skipwhite
+syn keyword graphqlStructure query mutation fragment nextgroup=graphqlName skipwhite
+syn keyword graphqlStructure directive nextgroup=graphqlDirective skipwhite
+syn keyword graphqlStructure extend nextgroup=graphqlStructure skipwhite
+syn keyword graphqlStructure schema nextgroup=graphqlFold skipwhite
+
+syn match graphqlDirective  "\<@\h\w*\>"   display
+syn match graphqlVariable   "\<\$\h\w*\>"  display
+syn match graphqlName       "\<\h\w*\>"    display
+syn match graphqlType       "\<_*\u\w*\>"  display
+
+" https://spec.graphql.org/October2021/#ExecutableDirectiveLocation
+syn keyword graphqlDirectiveLocation QUERY MUTATION SUBSCRIPTION FIELD
+syn keyword graphqlDirectiveLocation FRAGMENT_DEFINITION FRAGMENT_SPREAD
+syn keyword graphqlDirectiveLocation INLINE_FRAGMENT VARIABLE_DEFINITION
+" https://spec.graphql.org/October2021/#TypeSystemDirectiveLocation
+syn keyword graphqlDirectiveLocation SCHEMA SCALAR OBJECT FIELD_DEFINITION
+syn keyword graphqlDirectiveLocation ARGUMENT_DEFINITION INTERFACE UNION
+syn keyword graphqlDirectiveLocation ENUM ENUM_VALUE INPUT_OBJECT
+syn keyword graphqlDirectiveLocation INPUT_FIELD_DEFINITION
+
+syn keyword graphqlMetaFields __schema __type __typename
+
+syn region  graphqlFold matchgroup=graphqlBraces start="{" end="}" transparent fold contains=ALLBUT,graphqlStructure
+syn region  graphqlList matchgroup=graphqlBraces start="\[" end="]" transparent contains=ALLBUT,graphqlDirective,graphqlStructure
+
+if main_syntax ==# 'graphql'
+  syn sync minlines=500
+endif
+
+hi def link graphqlComment          Comment
+hi def link graphqlOperator         Operator
+
+hi def link graphqlBraces           Delimiter
+
+hi def link graphqlBoolean          Boolean
+hi def link graphqlNull             Keyword
+hi def link graphqlNumber           Number
+hi def link graphqlString           String
+
+hi def link graphqlDirective        PreProc
+hi def link graphqlDirectiveLocation Special
+hi def link graphqlName             Identifier
+hi def link graphqlMetaFields       Special
+hi def link graphqlKeyword          Keyword
+hi def link graphqlStructure        Structure
+hi def link graphqlType             Type
+hi def link graphqlVariable         Identifier
+
+let b:current_syntax = 'graphql'
+
+if main_syntax ==# 'graphql'
+  unlet main_syntax
+endif