Ambient-Oriented Programming

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at:tutorial:basic [2007/04/17 17:23] – tvcutsemat:tutorial:basic [2007/04/17 17:30] – tvcutsem
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 ==== Numerical data types ==== ==== Numerical data types ====
  
-AmbientTalk supports numbers and fractions which represent what other languages call integers and floating point numbers, respectively.  +AmbientTalk supports numbers and fractions which represent what other languages call integers and double precision floating point numbers, respectively.
  
-Note that since numerical types are objects in AmbientTalk, the traditional operators +,-,*,/, >, <, <=, >=, =, !=  are nothing but syntactic sugar for method invocations. Therefore,  //1+1// is internally translated into //1.+(1)//. Unary operators are just applications, e.g. //-5// is internally translated into //-(5)//. What follows are some basic examples of manipulations with numeric types:+Note that since numerical types are objects in AmbientTalk, the traditional operators %%+,-,*,/, >, <, <=, >=, =, !=%%  are nothing but syntactic sugar for method invocations. Therefore,  ''1+1'' is internally translated into ''1.+(1)''. Unary operators are just applications, e.g. ''-5'' is internally translated into ''-(5)''. What follows are some basic examples of manipulations with numeric types:
 <code> <code>
 >1.inc() >1.inc()
 >>2 >>2
->-1.abs() 
->>1 
 >1.cos() >1.cos()
 >>0.5403023058681398 >>0.5403023058681398
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 >>2 >>2
 </code> </code>
 +
 +Beware of the precedence rules for function application versus method invocation, which may lead to unexpected results, e.g.:
 +<code>
 +>-1.abs()
 +>>-1
 +</code>
 +This code is interpreted as ''-(1.abs())'', hence the result.
  
 Numbers also support some useful iterator methods such as: Numbers also support some useful iterator methods such as:
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 ==== Booleans ==== ==== Booleans ====
    
- +As any native type, booleans are objects so, they respond to keyword messages such as:
-AmbientTalk supports infix operators for booleans as &, | and !. As any native type, booleans are objects so, they respond to keyword messages such as:+
 <code> <code>
 <booleanexpr>.ifTrue: { ...}  <booleanexpr>.ifTrue: { ...} 
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 </code> </code>
  
-**=** and **!=** are the infix operators for equality and inequality. **true** and **false** are the boolean constant objects. What follows is some basic examples of boolean manipulation:+''='' and ''!='' are the infix operators for equality and inequality. The prefix operator ''!'' represents logical negation. ''true'' and ''false'' are the prototypical boolean singleton objects. What follows is some basic examples of boolean manipulation:
 <code> <code>
 >(0 < 1).ifTrue: { 0 }  >(0 < 1).ifTrue: { 0 } 
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 </code> </code>
  
-Boolean infix operators such as & and | are not shortcut. Thus, both arguments will be evaluated. For lazy evaluation, you should use the natives methods. For example, false.and: { 1/0 } will return false without executing the second argument.+Compound boolean expressions can be created by means of a boolean's ''and:'' and ''or:'' methods, which both take a zero-argument closure as argument. For example, ''false.and: { 1/0 }'' will return ''false''. The block is not applied because a logical //and// with ''false'' always fails.
  
 ===== Control Flow Structures ===== ===== Control Flow Structures =====
at/tutorial/basic.txt · Last modified: 2020/02/09 22:05 by elisag