Difference between revisions of "Declaration"
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| − | + | == Syntax == | |
| − | + | All variables must be declared before they are used. In Mesham one may declare a variable via its value or explicit type. | |
| − | + | var name;<br> | |
| + | var name:=[Value];<br> | ||
| + | var name:[Type];<br> | ||
| − | + | Where ''name'' is the name of the variable being declared. | |
| − | |||
| − | |||
| − | ==Semantics== | + | == Semantics == |
| − | In the case of a value being specified | + | The environment will map the identifier to storage location and that variable is now usable. In the case of a value being specified then the compiler will infer the type via type inference either here or when the first assignment takes place.<br><br> |
| + | ''Note:'' It is not possible to declare a variable with the value ''null'' as this is a special, no value, placer and as such has no type. | ||
| + | == Examples == | ||
| − | == | + | function void main() { |
| + | var a; | ||
| + | var b:=99; | ||
| + | a:="hello"; | ||
| + | }; | ||
| − | + | In the code example above, the variable ''a'' is declared, without any further information the type is infered by its first use (to hold type String.) Variable ''b'' is declared with value 99, an integer and as such the type is infered to be both Int and allocated on multiple processes. | |
| − | |||
| − | |||
| − | |||
| − | |||
| − | + | function void main() { | |
| + | var t:Char; | ||
| + | var z:Char :: allocated[single[on[2]]]; | ||
| + | }; | ||
| + | |||
| + | Variable ''t'' is declared to be a character, without further type information it is also assumed to be on all processes (by default the type Char is allocated to all processes.) Lastly, the variable ''z'' is declared to be of type character, but is allocated only on a single process (process 2.) | ||
| + | |||
| + | ''Since: Version 0.41b'' | ||
| + | [[Category:sequential]] | ||
Latest revision as of 15:44, 15 April 2019
Syntax
All variables must be declared before they are used. In Mesham one may declare a variable via its value or explicit type.
var name;
var name:=[Value];
var name:[Type];
Where name is the name of the variable being declared.
Semantics
The environment will map the identifier to storage location and that variable is now usable. In the case of a value being specified then the compiler will infer the type via type inference either here or when the first assignment takes place.
Note: It is not possible to declare a variable with the value null as this is a special, no value, placer and as such has no type.
Examples
function void main() {
var a;
var b:=99;
a:="hello";
};
In the code example above, the variable a is declared, without any further information the type is infered by its first use (to hold type String.) Variable b is declared with value 99, an integer and as such the type is infered to be both Int and allocated on multiple processes.
function void main() {
var t:Char;
var z:Char :: allocated[single[on[2]]];
};
Variable t is declared to be a character, without further type information it is also assumed to be on all processes (by default the type Char is allocated to all processes.) Lastly, the variable z is declared to be of type character, but is allocated only on a single process (process 2.)
Since: Version 0.41b
