November 2001
Intermediate to advanced
218 pages
6h 22m
English
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Debugger
It
doesn’t matter how easy a language is to use, it usually
contains some bugs if it is more than a few lines long. To help deal
with bugs, the standard distribution of Ruby includes a debugger. In
order to start the Ruby debugger, load the debug library using the
command-line option -r debug. The debugger stops
before the first line of executable code and asks for the input of
user commands.
Here are the debugger commands:
b[reak] [<file|class>:]<line|method>Sets breakpoints
wat[ch]expressionSets watchpoints
b[reak]Displays breakpoints and watchpoints
del[ete] [n]Deletes breakpoints
disp[lay]expressionDisplays value of
expressionundisp[lay] [n]Removes display of
nc[ont]Continues execution
s[tep] [n]Executes next
nlines stepping into methodsn[ext] [n]Executes next
nlines stepping over methodsw[here]Displays stack frame
f[rame]Synonym for where
l[ist][<-|n-m>]Displays source lines from
ntomup [n]Moves up
nlevels in the stack framedown [n]Moves down
nlevels in the stack framefin[ish]Finishes execution of the current method
tr[ace] [on|off]Toggles trace mode on and off
q[uit]Exits debugger
v[ar] g[lobal]Displays global variables
v[ar] l[ocal]Displays local variables
v[ar] i[instance]objectDisplays instance variables of
objectv[ar] c[onst]objectDisplays constants of object
m[ethod] i[instance]objectDisplays instance methods of
objectm[ethod]class|moduleDisplays instance methods of the
classormoduleth[read] l[ist]Displays threads
th[read] c[ur[rent]]Displays current thread ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.