On Wed, Aug 21, 2013 at 3:30 AM, ivo welch ivo.we...@gmail.com wrote:
thx, deepayan: how is stopifnot better than
if (!all(...)) stop()
But I am not claiming that it is!
If you think it is not useful, then don't use stopifnot(), use stop()
instead, and tell your students to do so as well.
first, I think it would be more useful if it had an optional character
string, so users could write
stopifnot( is.matrix(m), m is not a matrix )
stop() allows for arbitrary strings
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I am using a variant of stopifnot a lot. can I suggest that base R
extends its functionality? I know how to do this for myself. this is
a suggestion for beginners and students. I don't think it would break
anything.
first, I think it would be more useful if it had an optional character
On Wed, Aug 21, 2013 at 12:11 AM, ivo welch ivo.we...@anderson.ucla.edu wrote:
I am using a variant of stopifnot a lot. can I suggest that base R
extends its functionality? I know how to do this for myself. this is
a suggestion for beginners and students. I don't think it would break
On Aug 20, 2013, at 14:41, ivo welch ivo.we...@anderson.ucla.edu wrote:
A second enhancement would be a smart string, which knows that
everything inside {{...}} should be evaluated.
I think one the HTML templating libraries (whisker or mustache or some such)
provides something not unlike
On Tue, Aug 20, 2013 at 11:41 AM, ivo welch ivo.we...@anderson.ucla.edu wrote:
I am using a variant of stopifnot a lot. can I suggest that base R
extends its functionality? I know how to do this for myself. this is
a suggestion for beginners and students. I don't think it would break
If all you care about is emulating static type checking, then you can also
accomplish the same thing with lambda.r using type constraints on function
definitions.
e.g.
f(m) %::% matrix : matrix
f(m) %as% { m }
f(as.data.frame(matrix(rnorm(12),nrow=3)))
Error in UseFunction(f, ...) : No
thx, deepayan: how is stopifnot better than
if (!all(...)) stop()
given that we have stopifnot() and I have seen it used often, I think
my two suggestions would make it better.
thx, michael: the %and% and %or% constructs are indeed relics of my
perl background. my own definition is
On Tue, Aug 20, 2013 at 6:00 PM, ivo welch ivo.we...@gmail.com wrote:
character string at the end of an existing function, stopifnot(). (2)
I think estrings (that behave like characters but are interpolated
before printout) are useful in the same way perl interpolated strings
are useful.
The
functionality is nice. syntax is weird. I think I would have
preferred an interpolate function call.
stop( i(class is `class(pi)` and $pi) )
three typing letters, too, and more logical. most importantly, I wish
we had some form of this in base R from the outset--whatever it is--so
that my
first, I think it would be more useful if it had an optional character
string, so users could write
stopifnot( is.matrix(m), m is not a matrix )
Another option is to just generate better error messages automatically, e.g.:
library(assertthat)
x - 1:10
assert_that(is.matrix(x))
Error: x
On 08/20/2013 11:41 AM, ivo welch wrote:
A second enhancement would be a smart string, which knows that
everything inside {{...}} should be evaluated.
stopifnot( is.matrix(m), m is not a matrix, but a {{class(m)}} )
a variant with more traditional syntax might be
if (!is.matrix(m))
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