Differences

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--- at:tutorial:basic [2007/04/04 11:24] – * elisag
+++ at:tutorial:basic [2007/04/05 10:01] – elisag
@@ Line 1: / Line 1: @@
 <note>
-**IN PROGRESS**
+**UNDER CONSTRUCTION!!**
-  - Could it be possible that the "table of contents" table in this page contains also a link to the actual page with the table of contents of the tutorial?
-  - (TOADD_1:) how to define and deal with multidimensional tables.
 </note>
@@ Line 31: / Line 29: @@
 Reference is just done by evaluating the variable.
-==== Tables ====
+===== Tables =====
 As in Pico, indexed tables represent what other languages call arrays or lists. Tables are unidimensional and their indexes range from 1 to the size of the table. As variables, one can define, assign and refer to a table. Table definition is also made  with the keyword **def** in the following form:
@@ Line 61: / Line 59: @@
 >>[1, [1, 2, ["a", "e", "i", "o", "u"], 4, 5], "ambientTalk"]
 </code>
+=== Table Splicing ===
+TODO!
 ==== Functions ====
@@ Line 75: / Line 77: @@
 >>25
 </code>
-Functions can call themselves recusively and as in Pico, functions can also be nested in the definitions other functions such as:
+This example also illustrates how functions are called. Calls to functions without parameters must also include the parenthesis.
+Functions have access to the enclosing environment of its definition as shown in the following example.
+<code>
+>def counter := 0
+>>0
+> def inc() { counter := counter + 1}
+>><closure:inc>
+>inc()
+>>1
+</code>
+Functions can call themselves recusively and they can also be nested in the definitions of other functions such as:
 <code>
 >def fac(n) {
@@ Line 83: / Line 97: @@
   inner(n,1)
 }
->>nil
+>><closure:fac>
 >fac(5)
 >>120
 </code>
-Variables and other functions defined locally to a function are only visible in the scope of the function where there were defined. Notice also that a function name can also be used just to refer the function but without calling it.
+Variables and functions defined locally to functions are only visible in the scope of the function where there were defined.  In the previous example, //fac// uses a local function //inner// that is only visible inside //fac// and its nested scopes, in the example //fac.inner.//
+=== Variable-Length Argument Functions ===
+You can create functions that take an arbitrary  number of arguments by means of the splicing operator **@** as shown below:
+<code>
+>def sum(@args){ {
+  def total := 0;
+  foreach: { |el|  total := total + el } in: args;
+  total}
+>><closure:sum>
+>sum(1,2,3)
+>>6
+</code>
+When the //sum// function is called, the arguments are passed to the function in a table called //args// which can also be modified inside the body of the function. An alternative definition of the //sum// function follows:
+<code>
+>def sum(a, b, @rest){ {
+  def total := a + b;
+  foreach: { |el|  total := total + el } in: rest;
+  total}
+>><closure:sum>
+>sum(1,2,3)
+>>6
+</code>
+In this example the //sum// function accepts an arbitrary number of arguments as long as two arguments, //a// and //b//, are supplied. //a// and //b// are thus considered as mandatory arguments. A function can also declare optional arguments as shown below:
+<code>
+>def incr( number, step := 1){ number + step}
+>><closure:incr>
+>incr(3)
+>>4
+>incr(3,3)
+>>6
+</code>
+==== Closures and Blocks ====
+The function name can also be used just to refer the function but without calling it. TODO!
 Unlike Pico, AmbientTalk doesn't support function assigment. However, one can assign functions to variables. This means that internally a closure will be created and assigned to the variable. What follows is an example of such manipulation: