Terry Babbey writes:
I find I am really struggling trying to learn the syntax and variables for the various commands. Would an understanding of Python help me to understand the Zope commands better and is there good documentation for Python that does not expect the reader to have a large background knowledge? I do not think that an understanding of Python will help you much with DTML (of cause, it would not harm but help, but not too much).
In DTML, you only have to do with Python expressions: you see them enclosed in "...". Python expressions are a small part of Python (which is small by itself!). You have: the usual arithmetic operators: +, -, *, /, % strings: enclosed in '...', '''...''' or "...", """...""" (the two latter forms will not work in DTML!) lists: [], [1,2,3], ['a','b','c','d'] with methods "append(element)" and "insert(where,element)" (and some more) tuples: (), (1,), (1,2,3,), ('a','b') with '+' as concatenation and [i] for subscription dictionaries: {}, { 1: 'a'}, { 'a' : 'AAA', 'b' : 'BBB',} i.e. sets of key/value pairs. They support "[key]" for subscription. They have methods "update(dict)" and "clear()", "get(key,default=None)". functions: called by "function(argumentlist)", e.g. "int('0')", "sql_method(user='dieter',city='St. Ingbert') Arguments can be positional or keyword. Arguments can have default values and then be omitted in function calls. instances (of classes): with the infix '.' operator for attribute/method access: e.g. "[].append(1)", "[].insert(0,'a')", "object.id". Functions of instances are called methods. They have as implicit (on call) first argument the object they belong to. exceptions: raised with "raise" and catched with try: protected code except: exception handling uncaught exceptions produce the tracebacks you sometimes see in Zope error pages. Strings, lists, and tuples together are called sequences. They are '+' as concatenation, '*' as repetition and '[i]' as subscription. You can use the infix operator 'in' to test for containment. The "len" function can be used to determine the number of elements. Like all object oriented systems, Python relies heavily on object classes and extension modules. They are much more voluminous and complex than Python itself. One such framework (set of intertwined modules and classes) is Zope. It, itself, is far more complex than the complete Python. Especially, its namespace handling and the powerfull acquisition adds significantly to the complexity. If you need them, you must get aquainted with the methods of the various Zope objects (folders, images, DTML methods, DTML documents, ...), too. The namespace object "_" provides much of the interface to Python. Look at its documentation in the DTML guide. In general, you do not need all arguements of DTML tags or Zope objects. You should have a rough feeling, what is there and go into details when you need it. Dieter