Data commit

Task/Topic-variable/PicoLisp/topic-variable-1.l

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+PicoLisp sets the value of the variable (symbol) '@' to the result of
+conditional and controlling expressions in flow- and logic-functions (cond, if,
+and, when, while, etc.).
+
+Within a function or method '@' behaves like a local variable, i.e. its value is
+automatically saved upon function entry and restored at exit.
+
+For example, to read the current input channel until EOF, and print the square
+of every item which is a number:

Task/Topic-variable/PicoLisp/topic-variable-2.l

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+(while (read)
+   (when (num? @)
+      (println (* @ @)) ) )
+abc   # Not a number
+7     # Number
+49    # -> print square
+xyz   # Not a number
+3     # Number
+9     # -> print square