[m-dev.] Contribution: Pretty Printing Library

[Ralph Becket]

Okay, I've added a new constructor label/2 which acts like nest/2
except that indentation is now specified using a string rather than
number of spaces.  In terms of compositional behaviour etc. it is
otherwise identical to nest/2.

examples.m contains a demonstration:

=== Arbitrary Objects with Depth Limiting ===

behold: two("three", 3, three(...), two(...))


behold: two("three", 3, three(...), two(...))


behold: two(
behold:   "three",
behold:   3,
behold:   three(...),
behold:   two(...)
behold: )

Note that because labels are just like nests, the label string
only gets printed as part of the indentation after newlines, so
there's no guarantee that a label will be printed if its argument
doc fits on the line.  Question: is this reasonable behaviour
(sorry, semantics)?

Something I should point out is that pprint.m depends upon some
library changes I just checked in, namely the addition of
func string__length/1 to string.m and func id/1 to std_util.m

Cheers,

Ralph

--
Ralph Becket      |      MSR Cambridge      |      rbeck at microsoft.com 
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