refactor(eval): use Hashy McHashFace instead of gperf

this removes gperf as a build dependency

src/nvim/generators/gen_eval.lua

@@ -1,9 +1,12 @@
 local mpack = require('mpack')
 
 local nvimsrcdir = arg[1]
-local autodir = arg[2]
-local metadata_file = arg[3]
-local funcs_file = arg[4]
+local shared_file = arg[2]
+local autodir = arg[3]
+local metadata_file = arg[4]
+local funcs_file = arg[5]
+
+_G.vim = loadfile(shared_file)()
 
 if nvimsrcdir == '--help' then
   print([[
@@ -20,7 +23,9 @@ package.path = nvimsrcdir .. '/?.lua;' .. package.path
 
 local funcsfname = autodir .. '/funcs.generated.h'
 
-local gperfpipe = io.open(funcsfname .. '.gperf', 'wb')
+local hashy = require'generators.hashy'
+
+local hashpipe = io.open(funcsfname, 'wb')
 
 local funcs = require('eval').funcs
 local metadata = mpack.unpack(io.open(metadata_file, 'rb'):read("*all"))
@@ -38,21 +43,15 @@ local funcsdata = io.open(funcs_file, 'w')
 funcsdata:write(mpack.pack(funcs))
 funcsdata:close()
 
-gperfpipe:write([[
-%language=ANSI-C
-%global-table
-%readonly-tables
-%define initializer-suffix ,0,0,BASE_NONE,NULL,NULL
-%define word-array-name functions
-%define hash-function-name hash_internal_func_gperf
-%define lookup-function-name find_internal_func_gperf
-%omit-struct-type
-%struct-type
-VimLFuncDef;
-%%
-]])
 
-for name, def in pairs(funcs) do
+local names = vim.tbl_keys(funcs)
+
+local neworder, hashfun = hashy.hashy_hash("find_internal_func", names, function (idx)
+  return "functions["..idx.."].name"
+end)
+hashpipe:write("static const EvalFuncDef functions[] = {\n")
+for _, name in ipairs(neworder) do
+  local def = funcs[name]
   local args = def.args or 0
   if type(args) == 'number' then
     args = {args, args}
@@ -62,7 +61,10 @@ for name, def in pairs(funcs) do
   local base = def.base or "BASE_NONE"
   local func = def.func or ('f_' .. name)
   local data = def.data or "NULL"
-  gperfpipe:write(('%s,  %s, %s, %s, &%s, (FunPtr)%s\n')
+  hashpipe:write(('  { "%s", %s, %s, %s, &%s, (FunPtr)%s },\n')
                   :format(name, args[1], args[2], base, func, data))
 end
-gperfpipe:close()
+hashpipe:write('  { NULL, 0, 0, BASE_NONE, NULL, NULL },\n')
+hashpipe:write("};\n\n")
+hashpipe:write(hashfun)
+hashpipe:close()