User:CBM-c-
Ciao,
I am _c_, an Italian Vectorscripter since many years. Some of you might know me as Orso from Vectorlab or the comments on the present Developer wiki. I feel very comfortable with Vectorscript but will now switch over to Python for even more power. I will try to share here comments, problems -and solutions- from the point of view of a non-programmer. --_c_ (talk) 08:13, 17 May 2015 (EDT)
If you add comments, please use the full wiki formatting, easily available clicking on Advanced while on edit mode and don't forget to sign up your comment using --~~~~!
Vectorlab Archives
Here is the List Browsers article from the now dead Vectorlab site:
- List Browsers ( Vectorlab ListBrowsers Web Archives.zip)
I stored some of the Vectorlab sites:
VS <> Py Rosetta Stone
Description | Vectorscript | Python |
---|---|---|
Statement ending: | Semicolon always needed
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Semicolon needed only for multiple statements on one line:
Error Message: SyntaxError: invalid syntax |
Case sensitivity | Not case sensitive:
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Case sensitive:
Error Message: AttributeError: 'module' object has no attribute 'vs.ALRTDIALOG' |
Empty brakes for functions
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Can be without brakets
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Can't be without brakets
Error Message: - none! be careful! - |
Empty handles
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Variable scope
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Global wins over local:
{ GLOBAL ACCESS } { parent of subroutine "Increment" } PROCEDURE Main; VAR { good praxis: label globals with "g" } gIndex, gNum : INTEGER; { subroutine } PROCEDURE Increment; BEGIN { gNum is not defined in this subroutine the parser climbs up parent containers until it finds a declaration for the var gNum. In this case it can be found in Main } gNum := gNum +1; SysBeep; END; BEGIN gNum := 10; { init } FOR gIndex := 1 TO 10 DO Increment; { increments the variable gNum } AlrtDialog(Concat(gNum)); { returns 20 } END; Run(Main); |
Local wins over global:
# LOCAL ACCESS # subroutine def Increment(): # gNum is not defined in this subroutine # the parser creates a local instance of the var gNum! gNum +=1 vs.SysBeep gNum = 10 # init for gIndex in range(1, 10): Increment # increments the variable gNum # but only inside Increment! vs.AlrtDialog(str(gNum)) # returns 10! The global var didn't set # GLOBAL ACCESS: CORRECT # subroutine def Increment(): # gNum is not defined in this subroutine # tell the parser that you want to edit gNum global! global gNum gNum +=1 vs.SysBeep() gNum = 10 # init # please observe that the range is NOT 1, 10! for gIndex in range(0, 10): Increment() # increments the variable gNum # but only inside Increment! vs.AlrtDialog(str(gNum)) # returns 20 # GLOBAL ACCESS: WRONG # subroutine def Increment(): # gNum is not defined in this subroutine # tell the parser that you want to edit gNum global! global gNum gNum +=1 vs.SysBeep() # no init! for gIndex in range(0, 10): Increment() # increments the variable gNum # but only inside Increment! vs.AlrtDialog(str(gNum)) # rises error Error Message: NameError: global name 'gNum' is not defined |
FOR statements | Runs including last value:
{ runs 3 times! 1, 2 and 3 } FOR i := 1 TO 3 DO AlrtDialog(Concat(i)); |
Runs excluding last value:
# runs 2 times! 1 and 2 for i in range(1, 3): vs.AlrtDialog(str(i)) |
Colors |
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Warning: don't forget the brakets:
Error Message: - none! be careful! - |
Concatenate text | Supports implicit conversion:
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Doesn't support implicit conversion:
Error Message: TypeError: unsupported operand type(s) for +: 'int' and 'str' |
Encryption | Whatever .vs or .px file is linked through your includes, will be encrypted upon running the encrypt command. More infos about standard Vectorscript (Pascal) encryptions are here. | Create list of your included files in an xml file.
For encryption in Python there are difficulties. Instructions from Vlado on the Techboard, search for "problems-encrypting-a-python-script" (at the moment we cannot add external links to the present wiki). |
Python version | import sys
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"import vs" | import vs # do I need this?
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Caching
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varPersistentPythonEngine = 412 { Boolean }
In the SDK starting from VW 2014 we can read: When True the Python engine is the same for the execution of all scripts, this solves some issues with Py_Initialize and Py_Finalize. For example, when debugging externally python leaves threas that cause crash if Py_Initialize and Py_Finalize is used for each script call. So, this allows the engine to be preserved between calls, however Vectorworks will delete all custom modules and objects defined in the engine prior each execution. |
Lists
Lists are powerful in Python, below some fascinating lists manipulations. They remind me of Applescript:
months = "Jan Feb Mar Apr May Jun Jul" months = months.split() # no splitter defined and it will use the empty space --> ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul'] months[2] # --> 'Mar' note that the index is 0-based months2 = "Jan, Feb, Mar, Apr, May, Jun, Jul" months2.split(', ') # --> ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul'] use comma and empty space as splitter months.append('Jul') # --> ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul'] append adds an item to a list months.pop() #- -> 'Jul' pop fetches the last item of a list ', sunny '.join(months) # --> ', sunny Jan, sunny Feb, sunny Mar, sunny Apr, sunny May, sunny Jun, sunny Sep' '-'.join(months[1:3]) # --> 'Feb-Mar' del months[2] # --> ['Jan', 'Feb', 'Apr', 'May', 'Jun', 'Jul'] months = {1: 'Jan', 2: 'Feb', 3: 'Mar'} # --> {1: 'Jan', 2: 'Feb', 3: 'Mar'}
Errors
Python Error Messages:
BaseExceptions:
+-- SystemExit +-- KeyboardInterrupt +-- GeneratorExit +-- Exception +-- StopIteration +-- ArithmeticError | +-- FloatingPointError | +-- OverflowError | +-- ZeroDivisionError +-- AssertionError +-- AttributeError +-- BufferError +-- EOFError +-- ImportError +-- LookupError | +-- IndexError | +-- KeyError +-- MemoryError +-- NameError | +-- UnboundLocalError +-- OSError | +-- BlockingIOError | +-- ChildProcessError | +-- ConnectionError | | +-- BrokenPipeError | | +-- ConnectionAbortedError | | +-- ConnectionRefusedError | | +-- ConnectionResetError | +-- FileExistsError | +-- FileNotFoundError | +-- InterruptedError | +-- IsADirectoryError | +-- NotADirectoryError | +-- PermissionError | +-- ProcessLookupError | +-- TimeoutError +-- ReferenceError +-- RuntimeError | +-- NotImplementedError +-- SyntaxError | +-- IndentationError | +-- TabError +-- SystemError +-- TypeError +-- ValueError | +-- UnicodeError | +-- UnicodeDecodeError | +-- UnicodeEncodeError | +-- UnicodeTranslateError +-- Warning +-- DeprecationWarning +-- PendingDeprecationWarning +-- RuntimeWarning +-- SyntaxWarning +-- UserWarning +-- FutureWarning +-- ImportWarning +-- UnicodeWarning +-- BytesWarning +-- ResourceWarning