lua - In trepl or luajit, how can I find the source code of a library I'm using? -

let's i'm working lua library installed using luarocks, , want see definition of function library. in ipython in use

??function_name

to see definition in terminal, in matlab use

which function_name

then use editor @ path returned which. how similar find function definition lua library?

in 'plain' lua/jit, can debug.getinfo( func ) , table containing (among others) fields short_src, source , linedefined.

for lua functions, short_src filename or stdin if defined in repl. (source has different format, filenames prefixed @, = prefix used c functions or stuff defined interactively, , loaded functions, actual string loaded.)

you can pack in function like

function sourceof( f )     local info = debug.getinfo( f, "s" )     return info.short_src, info.linedefined end 

or maybe start editor , point there, e.g. (for vim)

function viewsource( f )     -- info & check it's file     local info = debug.getinfo( f, "s" )     local src, line = info.source, info.linedefined     if src == "=[c]"    return nil, "is c function."  end     local path = src:match "^@(.*)$"     if path         -- start vim (or other editor if adapt format string)         return os.execute( ("vim -fr %q +%d"):format( path, line ) )     end     return nil, "was defined @ run time." end 

and fun, here's yet version returns code if can find somewhere. (this work functions have been generated @ run time, e.g. calling load, , no source file exists. work in other direction dumping loaded snippet temp file , opening that…)

-- helper extract source block defining function local function funclines( str, line1, linen, filename )     -- if linedefined / lastlinedefined 0, main chunk's function     if line1 == 0 , linen == 0         filename = filename , filename.." (main chunk)"                              or "(chunk defined @ run time)"         return "-- "..filename.."\n"..str     end     -- add line info file name or use placeholder     filename = filename , filename..":"..line1 or "(defined @ run time)"     -- source block     local phase, i, j, k1, kn = 1, line1-1, linen-line1+1     if == 0  phase, k1 = 2, 0  end     pos in str:gmatch "\n()"         if phase == 1             = - 1 ; if == 0  k1, phase = pos, 2  end          else -- phase == 2             j = j - 1 ; if j == 0  kn = pos-2 ; break  end         end     end     return "-- "..filename.."\n"..str:sub( k1, kn ) end  function dumpsource( f )     -- info & line numbers     local info = debug.getinfo( f, "s" )     local src, line, lastline = info.source, info.linedefined, info.lastlinedefined     -- can't c function     if src == "=[c]"  return nil, "is c function."  end     if src == "=stdin"  return nil, "was defined interactively."  end     -- files, fetch definition     local path = src:match "^@(.*)$"     if path         local f = io.open( path )         local code = f:read '*a'          f:close( )         return funclines( code, line, lastline, path )     end     -- otherwise `load`ed, `source`/`src` _is_ source     return funclines( src, line, lastline ) end 

a closing remark: if paste code lua/jit repl, locals disappear between definitions, because every line (or minimal complete group of lines) own chunk. common fix (that know) wrap block do*paste*end, alternative load[[*paste*]]() (possibly more =s [===[ , ]===].) if paste way, above dumpsource (or other function using debug.getinfo) able source of function(s). means if defined nice function it's gone history , scroll buffer, can recover in way (if defined loading , not directly feeding interpreter). saving source in file possible without copy-pasting , not require editing out >> prompts.