NetAlive Documentation

File Widget

Inputs 8-11: data inputs (all the same).
Outputs 2-4: data outputs (all the same).
Input 7: address (standard interpretation).

Read or write files.

Behavior

Inputs get concatenated with implied synchronization into a single input value. However, "Asynchronous" simply routes input messages to an input value. Writes input values to the specified file.

Reads the specified file and transfers its contents to all outputs.

Appearance

Invisible.

Interactive Demonstration

Press to invoke file.net.

Be aware that the demo has four parts, three using the same file and one using a different one. The common file links its three parts in an important way:

The first row has a file widget with an input but no output. Type into the "Write to file" box and press enter. This writes your type-in to the common file. (The common file is in the Net Alive! temporary area, so it will persist until you do a "Control -- Clear Cache" from the menu bar.)

The second row has a file widget with an output but no input. When connected this way, a file widget produces one message when the application starts and is then silent. Thus, you can type into the top row as much as you want and the "Read from file" display does not change (try it). To update the "Read from file" display, stop the application and start it again (you can do this by pressing the "rocket" button twice).

The third row has a file widget with both an input and output. When connected this way, inputs get written to the file and simultaneously create an output message with the file's contents. However, the output message is the old contents of the file. In other words, if the file contains "one" and a message arrives with "two," the file ends up with "two" and a message is produced with "one." Try typing into "Write-read to file" and observe the value on the right changing, but delayed by one type-in.

The bottom row uses a state monitor widget attached to a different file. A state monitor widget works like a file widget with both input and output connected. However, a state monitor widget displays its contents.


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