Normalize Whitespace

Replace any sequence of whitespace by a single one.

It is particular useful if the output is a little messy: you can put extra spaces and new lines and it will still be valid.

Consider this example that prints a table but, for some reason, it uses only a single space as separator:

>>> print("Name Age kev 22 luc 23")
Name Age kev 22 luc 23

It looks ugly, does it?

We can add extra spaces and new lines to write a better example and combine it with +norm-ws so those extra spaces do not count.

>>> print("Name Age kev 22 luc 23")     # byexample: +norm-ws
Name    Age
kev     22
luc     23

Here is another example, this time written in Ruby:

>> Array(0...20)				# byexample: +norm-ws
=> [0,   1,  2,  3,  4,  5,  6,  7,  8,  9,
   10,  11, 12, 13, 14, 15, 16, 17, 18, 19]

Empty lines at the begin are ignored by default

Consider the following "\n \nSome line" output. The following three examples matches because by default byexample discards any empty line at the begin of the output.

>>> someline = "\n  \nSome line"

>>> print(someline)  # OK: <...> captures the empty lines
<...>
Some line

>>> print(someline)  # OK too: the same reason above
<...>Some line

>>> print(someline)  # OK: byexample ignores the empty lines "as if" a <...> was there
Some line

byexample understands as “empty lines” lines made entirely of spaces and tabs ended with a new line. It is subtle but such definition does not include indentation.

Consider the following "\n \n Some indented line":

>>> someindented = "\n  \n  Some indented line"

>>> print(someindented)  # FAIL: the example is not expecting indentation    # byexample: +pass
<...>
Some indented line

>>> print(someindented)  # OK: <...> captures all including the indentation
<...>Some indented line

>>> print(someindented)  # FAIL: byexample ignores the empty lines but not the indentation   # byexample: +pass
Some indented line

When +norm-ws is enabled, those two FAIL examples will work because byexample relaxes the definition of empty lines and replaces by “any whitespace” which the indentation gets included:

>>> print(someindented) # byexample: +norm-ws
<...>
Some indented line

>>> print(someindented)  # byexample: +norm-ws
Some indented line

New in byexample 11.0.0: before 11.0.0 it was up to the user to put a <…> or similar to ignore the empty lines at the begin (or use +rm=~ combined with +norm-ws). Since 11.0.0 this is the default. If you want to old behavior you can use the flag -ignore-first-empty-lines