feat(vim): add basic syntax support for vim

src/vim/ftdetect/lean.vim

@@ -0,0 +1,2 @@
+au BufRead,BufNewFile *.ilean set ft=lean
+au BufRead,BufNewFile *.lean set ft=lean

src/vim/syntax/lean.vim

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+" Vim syntax file
+" Language:		Lean
+" Filename extensions:	*.lean, *.ilean
+" Maintainer:		Simon Cruanes
+" For version 5.x: Clear all syntax items
+" For version 6.x: Quit when a syntax file was already loaded
+if version < 600
+	syntax clear
+"elseif exists("b:current_syntax")
+"	finish
+endif
+
+if version >= 600
+  setlocal iskeyword=@,48-57,_,-,!,#,$,%
+else
+  set iskeyword=@,48-57,_,-,!,#,$,%
+endif
+
+" tabs = evil
+set expandtab
+
+syn case match
+
+" keywords
+syn keyword leanKeyword import prelude tactic_hint protected private noncomputable
+syn keyword leanKeyword definition renaming hiding exposing parameter parameters
+syn keyword leanKeyword begin "begin+" proof qed conjecture constant constants hypothesis lemma
+syn keyword leanKeyword corollary variable variables premise premises theory print theorem proposition
+syn keyword leanKeyword example abbreviation abstract open as export override axiom axioms inductive
+syn keyword leanKeyword with structure record universe universes alias help environment options
+syn keyword leanKeyword precedence reserve match infix infixl infixr notation postfix prefix
+syn keyword leanKeyword tactic_infix tactic_infixl tactic_infixr tactic_notation tactic_postfix
+syn keyword leanKeyword tactic_prefix eval check end reveal this suppose using namespace section
+syn keyword leanKeyword fields find_decl attribute local set_option extends include omit classes
+syn keyword leanKeyword instances coercions metaclasses raw migrate replacing calc have show suffices
+syn keyword leanKeyword by in at let forall fun exists if dif then else assume assert take obtain from
+
+syn match leanOp        ":"
+syn match leanOp        "="
+
+" constants
+syn keyword leanConstant # @ -> ∼ ↔ / == := <-> /\\ \\/ ∧ ∨
+syn keyword leanConstant ≠ < > ≤ ≥ ¬ <= >= ⁻¹ ⬝ ▸ + * - / λ
+syn keyword leanConstant → ∃ ∀
+
+" modifiers (pragmas)
+syn keyword leanModifier contained containedin=leanBracketEncl persistent notation visible instance trans-instance class parsing-only
+syn keyword leanModifier contained containedin=leanBracketEncl coercion unfold-full constructor reducible irreducible semireducible
+syn keyword leanModifier contained containedin=leanBracketEncl quasireducible wf whnf multiple-instances none decls declarations coercions
+syn keyword leanModifier contained containedin=leanBracketEncl classes symm subst refl trans simp congr notations abbreviations
+syn keyword leanModifier contained containedin=leanBracketEncl begin-end-hints tactic-hints reduce-hints unfold-hints aliases eqv
+syn keyword leanModifier contained containedin=leanBracketEncl localrefinfo
+
+" delimiters
+
+syn match       leanBraceErr   "}"
+syn match       leanParenErr   ")"
+syn match       leanBrackErr   "\]"
+
+syn region      leanEncl            matchgroup=leanDelim start="(" end=")" contains=ALLBUT,leanParenErr,leanModifier keepend
+syn region      leanBracketEncl     matchgroup=leanDelim start="\[" end="\]" contains=ALLBUT,leanBrackErr keepend
+syn region      leanEncl            matchgroup=leanDelim start="{"  end="}" contains=ALLBUT,leanBraceErr,leanModifier keepend
+
+syn keyword	leanTodo	containedin=leanComment TODO FIXME BUG FIX
+
+syn region      leanComment	start=+/-+ end=+-/+ contains=leanTodo
+syn match       leanComment     contains=leanTodo +--.*+
+
+" Define the default highlighting.
+" For version 5.7 and earlier: only when not done already
+" For version 5.8 and later: only when an item doesn't have highlighting yet
+if version >= 508 || !exists("did_lean_syntax_inits")
+  if version < 508
+    let did_lean_syntax_inits = 1
+    command -nargs=+ HiLink hi link <args>
+  else
+    command -nargs=+ HiLink hi def link <args>
+  endif
+
+  HiLink leanTodo               Todo
+
+  HiLink leanComment		Comment
+
+  HiLink leanKeyword            Keyword
+  HiLink leanConstant           Constant
+  HiLink leanModifier           Special
+  HiLink leanDelim              Keyword  " Delimiter is bad
+  HiLink leanOp                 Keyword
+
+  HiLink leanBraceError         Error
+  HiLink leanParenError         Error
+  HiLink leanBracketError       Error
+
+  delcommand HiLink
+end
+
+let b:current_syntax = "lean"
+
+" vim: ts=8 sw=8