What did students think about this course
"Why did you chose compiler development?"
| Lab exercises | including the following links to extra information & hints: |
|---|---|
| Introduction: | debugging flex, byacc and make |
| Exercise 1: | condensed man page for egrep and regular expressions used with flex |
| Exercise 2: |
lex manual
and
strings and comments
characters [local] and pre-processing [local] and syntax [local] |
| Exercise 3: | yacc manual and use of %left etc. and examples |
| Exercise 4: | |
| Exercise 5: | grammar and strings and comments and extensions |
| Exercise 6: | spim and simulator |
| New information added since lab manual printed |
|---|
exercise 2
In the example output, I have picked up adjacent white-space
characters to be a single lexeme using
[ \t\n]+but in the problem description and in the starting code I only pick up single white space characters using [ \t\n]I would prefer to do the former, but I have to do the latter to be able to recognise preprocessor commands properly - can you see why? If not, try changing the rule for white space to see what happens - you should get lots of messages from the checker. When you "make test" for the first time, you should see something like this:
echo your output is being redirected to "out1"
your output is being redirected to out1
./c_lexemes <data.c >out1
echo here are any error messages - look at "out1" for more details
here are any error messages - look at out1 for more details
grep OOPS out1
4 OOPS - #include <stdio.h> is a preprocessor_command (not white_space etc. - see following list)
4 OOPS - #define a(nasty)\
echo here is the final report, counting characters and lexemes
here is the final report, counting characters and lexemes
wc -c <data.c ; tail -20 out1
1197
numbers of lexemes & characters - 22/9/99 10:17 GMT
380 ignore(s) in 960 characters
0 float_number(s) in 0 characters
0 octal_int_number(s) in 0 characters
0 decimal_int_number(s) in 0 characters
0 hex_int_number(s) in 0 characters
0 preprocessor_command(s) in 0 characters
0 comment(s) in 0 characters
0 character(s) in 0 characters
0 keyword(s) in 0 characters
0 built_in_type(s) in 0 characters
0 identifier(s) in 0 characters
0 punctuation_or_operator(s) in 0 characters
0 punctuation(s) in 0 characters
0 operator(s) in 0 characters
0 string(s) in 0 characters
0 unknown(s) in 0 characters
237 white_space(s) in 237 characters
total: 617 lexemes in 1197 characters
As you can see, the checker is over-enthusiastic about pre-processor commands.
There is a second, rather larger set of test-data: bigdata.c You are welcome to try your program on this - remove the leading "#" characters from these 3 lines in the makefile to do so: # ./c_lexemes <bigdata.c >out2 # -grep OOPS out2 # wc -c <bigdata.c ; tail -20 out2Don't get bogged down trying to deal with some of the wierd things in this file before you have dealt with the simpler problems in the first data-file. |
| exercise 6
local copy of MIPS/SPIM documentation In 1998/9, Chris Whitworth reported that spim and xspim are available in /opt/undergrad under Linux, but not yet under SunOS/Solaris. You need to copy /opt/undergrad/share/trap.handler to your working directory first. |
If your program crashes at run-time, making a "core" file,
and you want to find out what line it went wrong at etc.,
on Suns do:
dbx program_name where quitor on Linux do: gdb program_name core where quit(This relies on using gcc -g, as with the makefiles I provide.)
|
If you have any questions about or corrections to any of the lab exercises, please email me so I can correct or improve the descriptions. Many thanks to everyone who asked questions and made suggestions.
I supervise the lab, helped by the demonstrators.
| January 1999 Exam |
|---|
|
The lex+yacc question (question one) is compulsory.
You have to answer 2 of the other 3 questions.
For questions three and four you can answer any 2 of the 3 parts. (Questions one and two have no optional parts.) |
You will get these (or something similar) in a handout at the end of the course:
Also, many of the lecture handouts include exercises that you may find helpful. Some simply use concepts in the handout, others explore beyond these limits. You are not obliged to do them, but I hope you will find them useful for revision or to prepare for the lab. I put answers into the Undergraduate Resource Centre (and they can be found via the list of handouts).
There are also suitable exercises in many of the recommended books etc.
I am very happy to discuss any of these with you during the lab or after lectures, or by email.
You are welcome to make educational, not-for-profit use of my work, but please give me credit when you do so.