Portal: Instructions

Utils behind Instructions

`ensure-list`	Ensure the input to be a list. If it has been a sequence, do nothing; otherwise, return a list of it
`print-return`	Print the input and return it.
`keep-number-reasonable`	If a number is out of range (defined by max-number-magnitude and min-number-magnitude), set it to the max / min value.
`count-points`	Count the number of points in a tree. Each atom and each pair of parentheses is regard as one point.
`truncate`	Truncate numbers to integers. For example, 100.5 would be truncated to 100 and -134.2 would be truncated to 134
`subst`	`subst [A B C]` would substitute all Bs in C with A
`contains-subtree`	Returns true if the first argument contains the second argument as a subtree
`containing-subtree`	Returns the smallest subtree of the first argument which contains the second argument
`all-items`	Returns a list of all items in the argument. Duplicates would be contained. Both sublists and atoms are considered as items.
`not-lazy`	If it is a list, return a non-lazy version of it. If it isn’t a list, return it as a list.