at:tutorial:metaprogramming
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision | ||
at:tutorial:metaprogramming [2007/05/04 02:44] – stimberm | at:tutorial:metaprogramming [2007/10/08 13:27] – * tvcutsem | ||
---|---|---|---|
Line 1: | Line 1: | ||
- | < | ||
- | |||
===== Metaprogramming ===== | ===== Metaprogramming ===== | ||
Line 14: | Line 12: | ||
>>7 | >>7 | ||
</ | </ | ||
- | However, these constructs are all **syntactic sugar**. Behind the scenes, they all perform message sends. The following code shows the equivalents of the previous code, but with the actual message sends: | + | However, these constructs are all **syntactic sugar** |
< | < | ||
>[5, 6, 7].at(2) | >[5, 6, 7].at(2) | ||
Line 24: | Line 22: | ||
</ | </ | ||
- | Another special AmbientTalk construct | + | In the first example above the message // |
==== Quasiquoting and splicing ==== | ==== Quasiquoting and splicing ==== | ||
+ | Quasiquoting and splicing are an advanced and powerful metaprogramming techniques that control the evaluation process and allow one to manipulate the evaluation process of the abstract syntax tree. | ||
- | === Qouting | + | === Quoting |
Any valid AmbientTalk expression can be quoted. This prevents the expression from being evaluated. Instead, it is returned literally. | Any valid AmbientTalk expression can be quoted. This prevents the expression from being evaluated. Instead, it is returned literally. | ||
Line 61: | Line 60: | ||
</ | </ | ||
- | Note that in '' | + | Note that in '' |
== Expressions == | == Expressions == | ||
- | To quote a complete expression, it has to be wrapped in parantheses: | + | To quote a complete expression, it has to be wrapped in parentheses: |
< | < | ||
Line 80: | Line 79: | ||
== Statements == | == Statements == | ||
- | Statements (definitions, | + | Statements (definitions, |
< | < | ||
Line 103: | Line 102: | ||
With this construct, all the elements of the literal table are evaluated. By quoting a literal table, all the elements are quoted instead of evaluated: | With this construct, all the elements of the literal table are evaluated. By quoting a literal table, all the elements are quoted instead of evaluated: | ||
< | < | ||
- | > | + | > |
>> | >> | ||
</ | </ | ||
Line 129: | Line 128: | ||
>[ 7, 8, 9, @upTo(4) ] | >[ 7, 8, 9, @upTo(4) ] | ||
>>[7, 8, 9, 1, 2, 3, 4] | >>[7, 8, 9, 1, 2, 3, 4] | ||
+ | >[ 7, 8, 9, upTo(4) ] | ||
+ | >>[7, 8, 9, [1, 2, 3, 4]] | ||
</ | </ | ||
+ | In the example above the elements of the table returned by invoking **upTo(4)** are added in place to the table in which the expression was spliced. | ||
Splicing can also be used in combination with quoting and unquoting. AmbientTalk provides the // | Splicing can also be used in combination with quoting and unquoting. AmbientTalk provides the // | ||
Line 159: | Line 161: | ||
The following example uses meta-programming and reflection to generate a proxy for an object that provides a given interface. The interface' | The following example uses meta-programming and reflection to generate a proxy for an object that provides a given interface. The interface' | ||
+ | |||
+ | < | ||
+ | TODO: Update code | ||
+ | </ | ||
< | < |
at/tutorial/metaprogramming.txt · Last modified: 2009/11/21 07:44 by tvcutsem