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digitalmars.D.learn - Moving from Python to D

reply "avarisclari" <weiglec.envisagegame gmail.com> writes:
Hello,

Sorry to bother you with something trivial, but I am having 
trouble translating a block of code I wrote in Python over to D. 
Everything else I've figured out so far. Could someone help me 
understand how to get this right?

Here's the python:

scene = scenes["title"]

while 1 == 1:
     next_choice = None
     paths = scene["paths"]
     description = scene["description"]
     lines = string.split("\n")

     for line in lines:
         if len(line > 55):
             w = textwrap.TextWrapper(width=45, 
break_long_words=False)
             line = '\n'.join(w.wrap(line))
         decription += line +"\n"
     print description



     #Shows the choices
     for i in range(0, len(paths)):
         path = paths[i]
         menu_item = i + 1
         print "\t", menu_item, path["phrase"]

     print "\t(0 Quit)"

     #Get user selection

     prompt = "Make a selection ( 0 - %i): \n" % len(paths)

     while next_choice == None:
         try:
             choice = raw_input(prompt)
             menu_selection = int(choice)

             if menu_selection == 0:
                 next_choice = "quit"
             else:
                 index = menu_selection - 1
                 next_choice = paths[ index ]

         except(IndexError, ValueError):
                 print choice, "is not a valid selection"

     if next_choice == "quit":
         print "Thanks for playing."
         sys.exit()
     else:
         scene = scenes[ next_choice["go_to"] ]
         print "You decided to:", next_choice["phrase"], "\n"
         if sys.platform == 'win32':
             os.system("cls")
         else:
             os.system("clear")

I've got the very last piece set up, using consoleD to use 
clearScreen(), but The rest I'm not sure how to translate. Sorry 
for my incompetence in advance.
May 07 2015
next sibling parent reply Nick Sabalausky <SeeWebsiteToContactMe semitwist.com> writes:
I'm not really sure exactly what parts are the issue, but I'll point out 
what I can:

On 05/07/2015 11:24 PM, avarisclari wrote:

 Hello,

 Sorry to bother you with something trivial, but I am having trouble
 translating a block of code I wrote in Python over to D. Everything else
 I've figured out so far. Could someone help me understand how to get
 this right?

 Here's the python:

 scene = scenes["title"]


It looks like scenes is a dictionary that stores dictionaries of 
strings? If so, then in D, scenes would be declared like this:

string[string][string] scenes;

Then the above line would be:

auto scene = scenes["title"]


 while 1 == 1:


In D, while(true) is probably prefered, but that's just a matter of 
style. 1==1 will work too.


      next_choice = None
      paths = scene["paths"]
      description = scene["description"]
      lines = string.split("\n")


Phobos (D's standard library) has a split:
http://dlang.org/phobos/std_array.html#split

Also one specifically for splitting lines:
http://dlang.org/phobos/std_string.html#splitLines

They're easier to use than it looks:
auto lines = description.split("\n");

or better yet (also handles mac and win-style properly):
auto lines = description.splitLines();



      for line in lines:


Standard foreach:

for(ref line; lines) {


          if len(line > 55):
              w = textwrap.TextWrapper(width=45, break_long_words=False)


Exists in Phobos:
http://dlang.org/phobos/std_string.html#wrap

I've never actually used it myself though.


              line = '\n'.join(w.wrap(line))


Join is easy:
http://dlang.org/phobos/std_array.html#join

result = (whatever array or range you want to join).join("\n")

But really, I don't think you'll need this entire loop at all, though. I 
would just strip all the newlines and feed the result to Phobos's 
wrap(). Probably something like:

auto description =
	scene["description"].replace("\n", " ").wrap(45);

That should be all you need for the word wrapping.


          decription += line +"\n"


D uses ~ to concatenate strings instead of +. In D, + is just for 
mathematical addition.


      print description


writeln(description);


      #Shows the choices
      for i in range(0, len(paths)):


foreach(i; 0..paths.length) {


          path = paths[i]
          menu_item = i + 1
          print "\t", menu_item, path["phrase"]


writeln("\t", menu_item, path["phrase"]);

      print "\t(0 Quit)"

      #Get user selection


// Get user selection


      prompt = "Make a selection ( 0 - %i): \n" % len(paths)


This is in phobos's std.conv: http://dlang.org/phobos/std_conv.html

So, either:

auto prompt = "Make a selection ( 0 - " ~
	paths.length.to!string() ~ "): \n";

or:

auto prompt = text("Make a selection ( 0 - ",
	paths.length, ~ "): \n")


      while next_choice == None:
          try:
              choice = raw_input(prompt)


The basic equivalent to raw_input would be readln():
http://dlang.org/phobos/std_stdio.html#readln

But, the library Scriptlike would make this super easy, thanks to a 
contributer:
https://github.com/Abscissa/scriptlike

Pardon the complete lack of styling in the docs (my fault):
http://semitwist.com/scriptlike/interact.html

So, it'd be:

import scriptlike.interact;
auto choice = userInput!int(prompt);


              menu_selection = int(choice)

              if menu_selection == 0:
                  next_choice = "quit"
              else:
                  index = menu_selection - 1
                  next_choice = paths[ index ]

          except(IndexError, ValueError):
                  print choice, "is not a valid selection"

      if next_choice == "quit":
          print "Thanks for playing."
          sys.exit()


I forget the function to exist a program, but if this is in your main() 
function, then you can just:

return;


      else:
          scene = scenes[ next_choice["go_to"] ]
          print "You decided to:", next_choice["phrase"], "\n"
          if sys.platform == 'win32':
              os.system("cls")
          else:
              os.system("clear")

 I've got the very last piece set up, using consoleD to use
 clearScreen(), but The rest I'm not sure how to translate. Sorry for my
 incompetence in advance.
May 07 2015
parent reply Nick Sabalausky <SeeWebsiteToContactMe semitwist.com> writes:
On 05/08/2015 12:06 AM, Nick Sabalausky wrote:

 On 05/07/2015 11:24 PM, avarisclari wrote:

 scene = scenes["title"]


 It looks like scenes is a dictionary that stores dictionaries of
 strings? If so, then in D, scenes would be declared like this:

 string[string][string] scenes;

 Then the above line would be:

 auto scene = scenes["title"]


BTW, D calls them "Associative Arrays" or "AA", instead of "dictionary". 
I *think* "dictionary" is what Python calls them, but I could be wrong.
May 07 2015
parent "avarisclari" <weiglec.envisagegame gmail.com> writes:
On Friday, 8 May 2015 at 04:08:03 UTC, Nick Sabalausky wrote:

 On 05/08/2015 12:06 AM, Nick Sabalausky wrote:

 On 05/07/2015 11:24 PM, avarisclari wrote:

 scene = scenes["title"]


 It looks like scenes is a dictionary that stores dictionaries 
 of
 strings? If so, then in D, scenes would be declared like this:

 string[string][string] scenes;

 Then the above line would be:

 auto scene = scenes["title"]


 BTW, D calls them "Associative Arrays" or "AA", instead of 
 "dictionary". I *think* "dictionary" is what Python calls them, 
 but I could be wrong.


Yup, thank you for the help.
May 08 2015
prev sibling next sibling parent reply "Chris" <wendlec tcd.ie> writes:
"Moving from Python to D"

always a good idea ;-)
May 08 2015
parent "Chris" <wendlec tcd.ie> writes:
On Friday, 8 May 2015 at 14:13:43 UTC, Chris wrote:

 "Moving from Python to D"

 always a good idea ;-)


You might be interested in this:

http://wiki.dlang.org/Programming_in_D_for_Python_Programmers

http://d.readthedocs.org/en/latest/examples.html#plotting-with-matplotlib-python
May 08 2015
prev sibling parent Russel Winder via Digitalmars-d-learn <digitalmars-d-learn puremagic.com> writes:
On Fri, 2015-05-08 at 03:24 +0000, avarisclari via Digitalmars-d-learn
wrote:

 Hello,
=20
 Sorry to bother you with something trivial, but I am having=20
 trouble translating a block of code I wrote in Python over to D.=20
 Everything else I've figured out so far. Could someone help me=20
 understand how to get this right?
=20
 Here's the python:


This is Python 2 not Python 3!

Do you have a definition for scenes so I can run the code. Are there any
tests of any sort?

For me Step 1 is to make this Python 3 and much more idiomatic Python.
Doing this will also make the route to a D implementation far more
obvious.


--=20
Russel.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder ekiga.n=
et
41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel winder.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder
May 08 2015