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Frequently Asked Questions & Frequently Made Errors.

1. Redefining -

One of the most frequently made errors in Pico is made by Scheme or Lisp programmers.

test-variable:1

This is not a definition of a variable, but a redefinition of the substraction operator with two formal arguments: test and variable.

In the same way,

test-function(x):x

is not the definition of a function, but a redefinition of the substraction operator with test and function(x) as the formal arguments.

In Pico, words in identifiers are separated by underscores!

2. Repeated Definitions

In Pico the semantics of ":" means to add something to the dictionary. This means that the following interaction with the transcript

x:1
f():x
x:3
f()

will yield 1! This can lead to subtle errors. If you encounter weird errors, and you think this might be the cause, just reset Pico and evaluate your pogram anew.