OpenEuphoria

1. "dumping" a map

• Posted by cjnwl Feb 17, 2023
• 2017 views

Hi,

I'm new to OE and learning the ropes as it were. I've written a few simple programs, and I'm now exploring maps, which I want to use ultimately for a largish personal project that I have.

So, in my tests I want to be able to dump a text representation of a complex map, which includes nested maps, and none of the map functions in section 8.32 of the manual allow me to do this. I therefore would like to write a function that reads all key/value pairs in order to display them on screen, and calls itself recursively if a value is a nested map, but I don't know how to check if a value is a map. Using the map() function returns 1 for integers too, so doesn't help me.

Can anyone point me in the right direction, either to a function that already does what I want, or to tell me how to check if a value is a map or not ?

3. Re: "dumping" a map

• Posted by petelomax Feb 17, 2023
• 1948 views

The only way you could achieve that sort of thing is to tag any nested dictionaries properly,
so instead of storing 7, you store {"map",7} and it is your responsibility to ensure that nothing
ever naturally occurs which could accidentally be mistaken for that. Equally you could have say
{"building_plot", width, depth, price, dictionary_id} whereby [4] is always a dict (or 0/absent).

Tags are a pretty minimal overhead, and will more than easily repay their rent by helping with debugging.

As for saving to disk, then instead of saving {"map",7} you would have to store something like {"map","customers"},
and one thing Phix does have is the ability to give a name to a dictionary when it is created, and retrieve the
dictionary-id from a name, but otherwise not much else. Dictionaries are meant to be transient anyway, so if you are
looking for more permanent storage you would be far better off just using an SQLite database or similar.

5. Re: "dumping" a map

• Posted by ghaberek (admin) Feb 17, 2023
• 1920 views

You hit the nail on the head. I was halfway through drafting my in-depth explanation above when I saw you chimed in.

Hey hey hey. I prefer to use the term proprietor, thank you very much. I'm running the shop and keeping the lights on, not trying to pass decree from on high. Although "Lord" does have a certain ring to it...

I wouldn't say "a lot" of processing is required if we're only talking about a single level of nesting. But for multi-level or heterogeneous nesting yeah, it's nearly impossible as-is.

Don't discount EDS either. It's a perfectly cromulent data store for simple things. SQLite should hopefully ship with 4.2, whenever we can get it out the door.

-Greg

7. Re: "dumping" a map

• Posted by petelomax Feb 17, 2023
• 1891 views

One other thing, that confirms almost everything just said, is that the Phix docs are littered with links to this generic "unwise" statement.

I have also added this to the Phix docs recently:

It might not be entirely unfair to say that Phix user defined types are an explict embodiment of duck typing:

type duck(object x) 
    return gait(x)=WADDLE and noise(x)=QUACK and shape(x)=DUCK 
end type 
duck d = wolf -- crashes, eg `typecheck error: d is "wolf"` 
              -- aka you cannot put a wolf in a duck house 

However duck typing usually means the polar opposite: taking control away from the programmer and bravely/stupidly carrying on long after things go wrong.
In contrast, Phix types are designed to stop with a clear and readable (and catchable) runtime error as soon after and as close as possible to the error/mistake.

9. Re: "dumping" a map

• Posted by cjnwl Feb 20, 2023
• 1580 views

Thanks all for your replies and advice.

At the moment I don't want to save anything to file, just display on screen in a readable format.

To give more context, I have an existing app which reads a text file and based on its contents generates text output. The existing app is written in gawk and comprises some 3500 lines of code. For some time I have wanted to port it to a multi-platform compilable version, and I'm looking at either OE/phix, or python. The current app relies heavily on gawk's associative arrays, with string keys, so I need an easy way to replicate this in OE. Maps seem to fit the bill, but for development and trouble-shooting purposes it would be great to be able to visualize the contents of a complex multi-level map structure.

And this is really just a learning exercise so that I can next leverage my new-found OE or Python knowledge to port an Excel/VBA which also relies heavily on data structures, but this is a much more ambitious project as I need to recreate Excel's tabbed GUI (though I don't need any formulas, just tabbed grids).

Anyway, your replies have given me food for thought, I will run some tests during the day to see if they lead anywhere.

11. Re: "dumping" a map

• Posted by ChrisB (moderator) Feb 20, 2023
• 1520 views

Hi

The simple answer to that is no.

I think Eu has just relied on checking syntax, and reporting errors as they arise. You can implement in a check a variable is 'right' before operating on it, but that's about it.

Cheers

Chris

13. Re: "dumping" a map

• Posted by ghaberek (admin) Feb 20, 2023
• 1521 views

Awhile ago I wrote mvc/mapdbg.e for Euphoria MVC (a web framework I started writing for redoing this website). Mapdbg helps trace out what I was doing with maps and to ensure I was properly freeing objects from eumem. It's meant to be a drop-in replacement for std/map.e that uses uses the debugging features in Euphoria 4.1 to parse your code for map allocations and it logs these events to the console using mvc/logger.e. It also includes a print_map() routine that attempts to nicely display the key/value pairs, and an print_maps() routine that will print all of the maps currently allocated. I plan to pull mvc/logger.e into Euphoria 4.2 but if it's useful, I will pull in mvc/mapdbg.e as well. (These would be moved to the std/ include directory.) If you want to try it out, just copy mvc/mapdbg.e and mvc/logger.e into an mvc/ directory in your project directory and then change your include std/map.e line to include mvc/mapdbg.e. You also need to define MAPDBG for it to do its job and LOG_DEBUG for it to show debug logs.

-- enable debug logging. optional. shows mapdbg looking through your code. 
with define LOG_DEBUG 
include mvc/logger.e 
 
-- enable map debugging. required. tracks map usage and allows print_map() below. 
with define MAPDBG 
include mvc/mapdbg.e as map 
 
object users = map:new() 
map:nested_put( users, {"alice","id"}, "alice" ) 
map:nested_put( users, {"alice","name"}, "Alice" ) 
map:nested_put( users, {"alice","email"}, "alice@example.com" ) 
map:nested_put( users, {"bob","id"}, "bob" ) 
map:nested_put( users, {"bob","name"}, "Bob" ) 
map:nested_put( users, {"bob","email"}, "bob@example.com" ) 
map:nested_put( users, {"carol","id"}, "carol" ) 
map:nested_put( users, {"carol","name"}, "Carol" ) 
map:nested_put( users, {"carol","email"}, "carol@example.com" ) 
 
ifdef MAPDBG then 
    print_map( users, /* nested = */ 1 ) 
end ifdef 

Output:

users@/maptest3.ex:9 (map #3) = { 
     3: {0x24D62C12,"bob",  map #5 = { 
       1: {0x369D9230,"id","bob"}, 
      10: {0x36DEAD19,"email","bob@example.com"}, 
      12: {0x0EAAA6CB,"name","Bob"}, 
  } 
}, 
    10: {0x1C0FF609,"carol",  map #6 = { 
       1: {0x369D9230,"id","carol"}, 
      10: {0x36DEAD19,"email","carol@example.com"}, 
      12: {0x0EAAA6CB,"name","Carol"}, 
  } 
}, 
    15: {0x053F7D1E,"alice",  map #4 = { 
       1: {0x369D9230,"id","alice"}, 
      10: {0x36DEAD19,"email","alice@example.com"}, 
      12: {0x0EAAA6CB,"name","Alice"}, 
  } 
}, 
} 

I've been revisiting IUP lately and it has a few options for easily creating a tabbed interface with grids of data. I'd be glad to help you out with that when you're ready.

Nope, sorry. Runtime errors crash. But you can use crash_routine to "catch" that crash before your program exits completely. When your crash routine is called, Euphoria has already written its ex.err so you can open and read that file if you need.

-Greg

15. Re: "dumping" a map

• Posted by cjnwl Feb 22, 2023
• 1433 views

Thanks @ghabarek and @euphoric for your replies, using "map_xxx" as the key works for now, and I'll definitely try your mapdbg routines going forward. I'll also take you up on your offer of help with IUP when I reach that point, as I've never worked on a GUI before, my main programming experience goes back 30 years to dBase and COBOL, and since then I've mainly written short scripts. My gawk app is in essence only that, a script that reads an input file and generates output, so no GUI or user interaction. And the Excel/VBA app is similar in that I use the Excel front-end to enter data, and then it's a VBA script that generates output based on the contents of the different tabs.

17. Re: "dumping" a map

• Posted by cjnwl Feb 22, 2023
• 1376 views

I can now use a nested_put|get to set or retrieve data, which is what I wanted :

 
map:nested_put(tables, {"m_kids", "m_test", "value"}, 125) 
writefln("\n" & map:nested_get(tables, {"m_kids", "m_test", "description"}) & "\n") 
 
map_dump(tables, 0) 

19. Re: "dumping" a map

• Posted by cjnwl Feb 22, 2023
• 1349 views
• Last edited Feb 24, 2023

With some global variables and a couple of wrapper functions :

-- map investigation 
 
include std/io.e 
include std/map.e 
 
 
integer  indent  = 4       -- spaces per sub-level 
sequence m_      = "m_"    -- submap indicator 
sequence prefix  = ">> "   -- prefix before submap name 
sequence postfix = " >"    -- postfix after submap name 
 
map      tables = new()  -- map to hold tables data 
map      kids   = new()  -- map to hold kids 
map      smap   = new()  -- map to hold submap 
 
 
procedure map_dump(map m, integer offset) 
    integer s = map:size(m) 
    sequence k = map:keys(m) 
    sequence v = map:values(m) 
 
    for i = 1 to s do 
        if sequence(k[i]) and equal(m_, k[i][1..2]) then 
            writefln("[][][][]", {repeat(32, offset), prefix, k[i], postfix}) 
            map_dump(v[i], offset+indent) 
        else 
            writefln("[][] = []", {repeat(32, offset), k[i], v[i]}) 
        end if 
    end for 
    return 
end procedure 
 
procedure my_nested_put(map m, sequence s, object v) 
    integer l = length(s) 
    sequence temp = s 
    for i = 1 to l-1 do 
	temp[i] = m_ & temp[i] 
    end for 
    map:nested_put(m, temp, v) 
    return 
end procedure 
 
function my_nested_get(map m, sequence s) 
    integer l = length(s) 
    sequence temp = s 
    for i = 1 to l-1 do 
	temp[i] = m_ & temp[i] 
    end for 
    return map:nested_get(m, temp) 
end function 
    
 
map:put(tables, "id", 1) 
map:put(tables, "name", "aaa") 
 
map:put(kids, 1, "alice") 
map:put(kids, 2, "tom") 
map:put(kids, 3, "wendy") 
map:put(tables, "m_kids", kids) 
 
map:put(smap, "test", "test") 
map:put(smap, "description", "long description") 
map:put(kids, "m_test", smap) 
map:put(tables, "m_test_2", smap) 
 
map_dump(tables, 0) 
 
--map:nested_put(tables, {"m_kids", "m_test", "value"}, 125) 
--writefln("\n" & map:nested_get(tables, {"m_kids", "m_test", "description"}) & "\n") 
 
--map_dump(tables, 0) 
 
writefln("\n============\n") 
 
object users = map:new()  
map:nested_put( users, {"m_alice","id"}, "alice" )  
map:nested_put( users, {"m_alice","name"}, "Alice" )  
map:nested_put( users, {"m_alice","email"}, "alice@example.com" )  
map:nested_put( users, {"m_bob","id"}, "bob" )  
map:nested_put( users, {"m_bob","name"}, "Bob" )  
map:nested_put( users, {"m_bob","email"}, "bob@example.com" )  
map:nested_put( users, {"m_carol","id"}, "carol" )  
map:nested_put( users, {"m_carol","name"}, "Carol" )  
map:nested_put( users, {"m_carol","email"}, "carol@example.com" )  
 
my_nested_put(users, {"carol", "age"}, 25) 
 
map_dump(users, 0) 
 
writefln("\n" & my_nested_get(users, {"carol", "email"})) 

21. Re: "dumping" a map

• Posted by cjnwl Feb 24, 2023
• 1075 views

Thanks, I'd missed that possibility.