Pre-compile regular expressions for speed

[UuuNyaa]

Purpose of the pull request

• Reduce the execution time of gen.py.

Description about the pull request

• I profiled gen.py and found that compiling the regular expressions takes a long time. profile_before.txt 817374612 function calls (815148474 primitive calls) in 308.347 seconds
• Pre-compiling the regular expressions makes it 3.7 times faster. profile_after.txt 126576412 function calls (126367374 primitive calls) in 82.795 seconds

• Output results changed slightly. The change has not yet been checked. results_diff.txt

  diff -ur build/results_original build/results > results_diff.txt

[UuuNyaa]

Even faster: 116304878 function calls (116087113 primitive calls) in 60.205 seconds

[nutti]

@UuuNyaa

Sorry for a late response. I merged this PR.