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at:tutorial:basic [2007/04/06 08:27] – * elisagat:tutorial:basic [2007/04/06 11:35] – * elisag
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 <note> <note>
-**IN PROGRESS: FIRST DRAFT!!** +**This Tutorial is still under heavy construction**
- +
-- TODO: Adding Table splicing, quasi-quoting?+
 </note> </note>
 ====== Functional and Imperative Programming ====== ====== Functional and Imperative Programming ======
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 >>[7,5] >>[7,5]
 </code> </code>
-Reference is just done by evaluating the variable. + 
 +The variable name is used to refer a variable. The variable is evaluated when referenced.  
 +<code> 
 +>x 
 +>>7 
 +</code>
  
 ===== Tables ===== ===== Tables =====
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 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> <code>
->def vocals := ["a", "e", "i", "o", "u"]+>def vowels := ["a", "e", "i", "o", "u"]
 >>["a", "e", "i", "o", "u"] >>["a", "e", "i", "o", "u"]
->table[3] := vocals+>table[3] := vowels
 >>[1, 2, ["a", "e", "i", "o", "u"], 4, 5] >>[1, 2, ["a", "e", "i", "o", "u"], 4, 5]
 >table[3][2] >table[3][2]
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 </code> </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 //vowels//, evaluating a series of comma-separated data types between square brackets (aka a tabulation) results in a table.
  
 <code> <code>
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 </code> </code>
  
-=== Table Splicing ===+==== Table Splicing ====
  
 TODO! TODO!
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 This example also illustrates how a function can be made private by means of lexical scope. Variables and functions defined locally to functions are only visible in the scope of the function where there were defined. Note that local //inner// function is only visible inside the //fac// function and its nested scopes. Thus, calling //fac.inner(2,3)// will return a lookup failure error. This example also illustrates how a function can be made private by means of lexical scope. Variables and functions defined locally to functions are only visible in the scope of the function where there were defined. Note that local //inner// function is only visible inside the //fac// function and its nested scopes. Thus, calling //fac.inner(2,3)// will return a lookup failure error.
    
-=== Variable-Length Argument Functions ===+==== Variable-Length Argument Functions ====
  
-You can create functions that take an arbitrary  number of arguments by means of the splicing operator **@** as shown below:+You can create functions that take an arbitrary number of arguments by means of the splicing operator **@** which splices the table containing the parameters into the argument list.
 <code> <code>
 >def sum(@args){ {  >def sum(@args){ { 
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 </code> </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:+When the //sum// function is called, the //args// table is spliced and passed as the argument list to the function. Note that the //args// table can also be modified inside the body of the function.  
 + 
 +Alternatively, we could define the //sum// function to take at least two numbers as shown below:
 <code> <code>
 >def sum(a, b, @rest){ {  >def sum(a, b, @rest){ { 
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 </code> </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:+In that case, the //sum// function still accepts an arbitrary number of arguments as long as two arguments are supplied. //a// and //b// are considered as mandatory arguments of the argument list.  
 + 
 +A function can also declare optional arguments as shown below. Optional arguments can be omitted in a function call. Internally, the default value provided in their definition is passed as the argument to the function. 
 <code> <code>
 >def incr( number, step := 1){ number + step} >def incr( number, step := 1){ number + step}
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 ===== Keywords ===== ===== Keywords =====
- 
  
 AmbientTalk supports keyword messages. We have already seen some examples of keyword messages in the previous sections such as the foreach structure. In AmbientTalk keywords are transformed by the parser into functions in the form: AmbientTalk supports keyword messages. We have already seen some examples of keyword messages in the previous sections such as the foreach structure. In AmbientTalk keywords are transformed by the parser into functions in the form:
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-The basic types in AmbientTalk are numbers, fractions, text, tables and booleans. In fact, these data types are nothing but objects and as such, they respond to a variety of native methods. This section shows some examples how to manipulate the basic types. The complete list of methods can be found in the language reference.+The basic types in AmbientTalk are numbers, fractions, text, tables and booleans. In fact, these data types are nothing but objects and as such, they respond to a variety of native methods. Objects will be the subject of the next chapter of the tutorial. This section explains the basic data types and includes some examples how to manipulate them. The complete list of methods can be found in the language reference.
  
 ==== Numerical data types ==== ==== Numerical data types ====
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 >"ambienttalk".explode() >"ambienttalk".explode()
 >>["a", "m", "b", "i", "e", "n", "t", "t", "a", "l", "k"] >>["a", "m", "b", "i", "e", "n", "t", "t", "a", "l", "k"]
->"one, two, three".split(", ")+>"one, two, three".split(",")
 >>["one", "two", "three"] >>["one", "two", "three"]
->"ambienttalk".replace: "[aeiou]" by: { |vowel| vowel.toUpperCase() }+>"ambienttalk".replace: "[aeiou]" by: { 
 + |vowel| vowel.toUpperCase()  
 +}
 >>"AmbIEnttAlk" >>"AmbIEnttAlk"
 >"A".toLowerCase() >"A".toLowerCase()
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 ==== Tables ==== ==== Tables ====
    
 +
 +We have already introduce how to define tables. Let us now focus on how to manipulate them with the native methods provided by the table object.
 +<code>
 +>[1,2,3].filter: {|e| e != 2 }
 +>>[1, 3]
 +>[1,2,3].map: { |i| i + 1 }
 +>>[2, 3, 4]
 +>def vowels := ["a", "e", "i", "o", "u"]
 +>>["a", "e", "i", "o", "u"]
 +>vowels.length
 +>>5
 +>vowels.at(1)
 +>>"a"
 +>vowels.atPut(1, "z")
 +>>"z"
 +>vowels
 +>>["z", "e", "i", "o", "u"]
 +>vowels.select(2,5).implode()
 +>>"eio"
 +>vowels.isEmpty()
 +>>false
 +</code>
 +
 +Tables also support some useful iterator methods such as:
 +<code>
 +>def sum:= 0; 
 +>>0
 +>[1,2,3].each: { |i| sum := sum + i }
 +>>nil
 +>sum
 +>>6
 +>def sumNnum (@args) {
 +  args.inject: 0 into: { |total, next| total + next}
 +}
 +>><closure:sumNnum>
 +>sumNnum(1,2,3)
 +>>6
 +</code>
  
 ==== Booleans ==== ==== Booleans ====
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 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. 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.
- 
  
 ===== Control Flow Structures ===== ===== Control Flow Structures =====
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      def pivot := table[(left+right) /- 2];      def pivot := table[(left+right) /- 2];
      def save := nil;      def save := nil;
-     while: { left <= right } do: {+        while: { left <= right } do: {
      while: { cmp(table[left], pivot) } do: {       while: { cmp(table[left], pivot) } do: { 
                 left := left + 1                  left := left + 1 
at/tutorial/basic.txt · Last modified: 2020/02/09 22:05 by elisag