Differences

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--- at:tutorial:basic [2007/04/05 10:02] – elisag
+++ at:tutorial:basic [2007/04/05 11:53] – elisag
@@ Line 30: / Line 30: @@
 ===== 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:
+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:
 <code>
 def t[ <size> ] { <expression> }
@@ Line 41: / Line 41: @@
 >>[1, 2, 3, 4, 5]
 </code>
-Although there is no special constructor for definition of multidimensional tables, a table entry can contain another table. This is internally stored as a unidimensional table whose entries are other tables.
+Although there is no special constructor for definition of multidimensional tables, a table entry can contain another table. This is internally stored as a unidimensional table whose entries are other tables.
 <code>
 >def vocals := ["a", "e", "i", "o", "u"]
@@ Line 52: / Line 52: @@
 </code>
-As shown in the definition of the varible "vocals", evaluating a series of comma-separated abstract grammar values between square brackets (aka a tabulation) results in a table.
+As shown in the definition of the varible //vocals//, evaluating a series of comma-separated abstract grammar values between square brackets (aka a tabulation) results in a table.
 <code>
@@ Line 76: / Line 76: @@
 >>25
 </code>
-This example also illustrates how functions are called. Calls to functions without parameters must also include the parenthesis.
+This example also illustrates how functions are called. Calls to functions without parameters must also include the parenthesis as shown below.
+<code>
+>def f(){nil}
+>><closure:f>
+>f()
+>>nil
+</code>
+The return value of a function is the result of the last statement executed. Functions must always return a value - i.e. they cannot be abstract. The example also illustrates how to create dumb function that doesn't do anything but returning the //nil// object.
 Functions have access to the enclosing environment of its definition as shown in the following example.
@@ Line 137: / Line 144: @@
 </code>
-===== Blocks =====
+===== Closures =====
 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:
+===== Blocks =====
-<code>
+Blocks.
->def sum := 0
+In AmbientTalk, blocks are merely syntactic sugar for anonymous closures (aka lambdas).  Blocks are creating using the {} braces in the form of:
->>0
+{ | <parlist> | <body>}
->sum := sum + 1
+If the block do not require any parameter, the |<parlist>| can be omitted.  Consider a basic block to sum two numbers:
->>1
+>{| a, b| a+ b} (3,2)
->sum := { | x, y| x + y }
+>>5
->>nil
+Note that the argument list passed to the block can define the different types of arguments previously explained.
->sum(1,2)
+>{ |a, b, @rest| def total := a + b; foreach: { |el| total := total + el} in: rest; total }(1,2,3)
+>>6
+AmbientTalk doesn’t support function assigment. However, one can assign blocks to variables. In order to call the block the name of the variable must be used. If the block defined parameters, these are required to the call as argument list. What follows is an example of such manipulation:
+>def square := { |x| x * x}
+>><closure:lambda>
+>square(1,2)
 >>3
-</code>