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op(tab);
table([
phone = x0-0000
key = 100
name = joeuser
address = mit
])
The example shows that tables are one of Maple's exceptions to the use of full evaluation. Tables,
arrays, and procedures use what is referred to as "last name evaluation". In essence, variables access
these objects by reference, not by value. To directly access the value (to copy it, for instance), you
need to use the op function described earlier.
An array is much like a table, except that you specify an integer range of subscripts. For example:
> arr := array(1..2, 1..2);
arr := array(1 .. 2, 1 .. 2, [])
> arr[1,1] := 1: arr[2,2] := 2:
> print(arr);
[ 1 arr[1, 2] ]
[ ]
[ arr[2, 1] 2 ]
11.5.4 Maple Initialization (UNIX)
When a Maple session begins, Maple looks for a file in your home directory called ~/.mapleinit and
reads it in. This provides you with a convenient way to do things like automatically load in packages
that you often use. All you need to do is use a text editor like emacs or ez to create the file
~/.mapleinit. Edit the file and place any Maple commands you want there in the same format that you
would enter them interactively.
11.6 Programming in Maple
Up until this point, discussion has been focused on only two statement types of the Maple language,
the "expression statement" (Ausdrucksanweisung) and the "assignment statement"
(Zuordnungsanweisung). We will now give an overview of some forms of programming statements. In
each case, we will give an outline of the syntax of the statement, a description of its meaning or effect,
and an example of its use. For more information on programming in Maple, you can refer to the Maple
V Programming Guide.
11.6.1 Control Structures
There are four important types of non-procedural statements that affect the flow of control of a
program:
• the for-while loop
• the if statement
• the break statement
• the next statement
Each of these structures is explained here. There are some other statements that affect flow of control
that have either already been introduced (done/quit/stop), or will be dealt with in the sections
Procedures and Error Handling.
11.6.1.1 For-While
The two syntactic forms of the for-while statement are:
for variable from start by change to finish while
condition do
statement-sequence
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