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Difference between revisions of "EDT:Language Overview"
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= Introduction = | = Introduction = | ||
| − | This essay gives an overview of the language. | + | This essay gives an overview of the language. |
| − | == | + | == Compilation <br> == |
| − | + | In relation to any modern programming language, an automated process converts source code from a relatively abstract form to a more concrete, platform-specific one. For example, the logic might be compiled into machine code, or into byte codes that can be read by a virtual machine. | |
| − | + | [ summarize typical compilation. identify how the EGL tech is different and why. ] | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | = Types and values = | |
| − | + | In general usage, a '''type''' such as integer or string defines a set of values and a set of operations that can be applied to those values. For example, integers are whole numbers that can be added, subtracted, and so forth; and the number 5 is a value of that type. | |
| − | + | The meaning is much the same in programming, where every value is “of a type.” The type defines the structure of the value and the set of operations that can be applied to the value. | |
| − | + | == Reference and value == | |
| − | + | In general, types are of two kinds, reference and value: | |
| − | + | *A '''reference type''' defines an '''object''', which is a value in a memory area that was allocated specifically to hold a value of the type. The object is referenced from some logic and is an instance of the type. In this case, the words ''value'' and ''instance'' are interchangeable. | |
| + | *A '''value type'''defines a value that is embedded in an object. | ||
| − | + | Also in general, a '''field declaration''' is a coded statement that has two effects: <br> | |
| − | + | *Declares a value of a type. | |
| + | *Names a memory area that provides access to the value. If the value is based on a reference type, the memory area holds an address or other detail that points to the value. If the value is based on a value type, the memory area contains the value. | ||
| − | + | Turning now to the syntax of EGL, consider the following field declarations:<br><br><br> | |
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Revision as of 14:27, 11 October 2011
Introduction
This essay gives an overview of the language.
Compilation
In relation to any modern programming language, an automated process converts source code from a relatively abstract form to a more concrete, platform-specific one. For example, the logic might be compiled into machine code, or into byte codes that can be read by a virtual machine.
[ summarize typical compilation. identify how the EGL tech is different and why. ]
Types and values
In general usage, a type such as integer or string defines a set of values and a set of operations that can be applied to those values. For example, integers are whole numbers that can be added, subtracted, and so forth; and the number 5 is a value of that type.
The meaning is much the same in programming, where every value is “of a type.” The type defines the structure of the value and the set of operations that can be applied to the value.
Reference and value
In general, types are of two kinds, reference and value:
- A reference type defines an object, which is a value in a memory area that was allocated specifically to hold a value of the type. The object is referenced from some logic and is an instance of the type. In this case, the words value and instance are interchangeable.
- A value typedefines a value that is embedded in an object.
Also in general, a field declaration is a coded statement that has two effects:
- Declares a value of a type.
- Names a memory area that provides access to the value. If the value is based on a reference type, the memory area holds an address or other detail that points to the value. If the value is based on a value type, the memory area contains the value.
Turning now to the syntax of EGL, consider the following field declarations: