sre_parse Module¶
The sre_parse module parses regular expression patterns into an abstract syntax tree used by the regex engine.
Complexity Reference¶
| Operation | Time | Space | Notes |
|---|---|---|---|
| Parse pattern | O(n) | O(n) | n = pattern length |
| Build AST | O(n) | O(n) | n = pattern complexity |
Parsing Regex Patterns¶
Analyzing Regex Structure¶
import sre_parse
# Parse pattern - O(n)
pattern = r'\d+@[\w.-]+\.\w+'
ast = sre_parse.parse(pattern)
# Examine structure - O(1)
print(ast)
# Shows the parse tree
# Pattern analysis
for item in ast:
print(f"Token: {item}")