Category:Elena: Difference between revisions
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== The simplest program == |
== The simplest program == |
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To create a simple console program we have to declare the |
To create a simple console program we have to declare the program symbol in the project root namespace: |
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program = |
program = |
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]. |
]. |
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Everything in ELENA is an object. To interact with it we have to send a message. The simplest ( |
Everything in ELENA is an object. To interact with it we have to send a message. The simplest (generic, i.e. without an explicit signature) message consists of an action and a parameter list. |
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The statement should be terminated by a dot ( |
The statement should be terminated by a dot (ELENA is inspired by Smalltalk and uses its syntax notations). |
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program = |
program = |
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]. |
]. |
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In our example the action is |
In our example the action is writeLine and the parameter list consists of a single literal constant. The message target is console object (implementing input / output operations with a program console). |
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Several message operations can be done in a single statement separated by a semicolon: |
Several message operations can be done in a single statement separated by a semicolon: |
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How are you? |
How are you? |
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We may read a user input by sending |
We may read a user input by sending readLine message without parameters: |
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program = |
program = |
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Hello Alex |
Hello Alex |
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Console::write method is similar to writeLine except that it writes to the output screen without a new line character. |
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== Declaring a variable == |
== Declaring a variable == |
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