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  user=> (re-pattern "\\d+")
  #"\d+"
  
  user=> (re-find (re-pattern "\\d+") "abc123def") 
  "123"
  
  ;; If you want to construct a regex pattern dynamically at run time,
  ;; then you need to use re-pattern to convert a string to a pattern
  ;; that can be used for matching.  But if your pattern is one you
  ;; write into the source code, it is more convenient to use the
  ;; #"pattern" syntax.  The previous example can be written as follows.
  user=> (re-find #"\d+" "abc123def") 
  "123"
  
  ;; Below are two examples that are equivalent in the patterns they
  ;; use, but the #"pattern" syntax helps significantly, because it lets
  ;; us avoid the requirement to escape every \ character with another \
  ;; character.  See the example with embedded comments below for more
  ;; detail on what the pattern matches.
  user=> (re-find #"\\\d+\s+\S+" "\\ it sh0uld match in \\5 here somewhere.")
  "\\5 here"
  
  user=> (re-find (re-pattern "\\\\\\d+\\s+\\S+")
                  "\\ it sh0uld match in \\5 here somewhere.")
  "\\5 here"
  
  ;; If you want to embed (ignored) whitespace and comments from #
  ;; characters until end-of-line in your regex patterns, start the
  ;; pattern with (?x)
  user=> (re-find #"(?x)  # allow embedded whitespace and comments
                    \\    # backslash
                    \d+   # one or more digits
                    \s+   # whitespace
                    \S+   # non-whitespace"
                  "\\ it sh0uld match in \\5 here somewhere.")
  "\\5 here"
  
  ;; Other pattern flags like Java's DOTALL, MULTILINE and UNICODE_CASE
  ;; pattern matching modes, can be set by combining these embedded flags
  
  ;; (?d) Unix lines (only match \newline)
  ;; (?i) Case-insensitive
  ;; (?u) Unicode-aware Case
  ;; (?m) Multiline
  ;; (?s) Dot matches all (including newline)
  ;; (?x) Ignore Whitespace and comments
  
  user=> (re-seq #"(?ix) test #Case insensitive and comments allowed"
                 "Testing,\n testing,\n 1 2 3")
  ("Test" "test")
  

  user=> (re-pattern "\\d+") #"\d+" user=> (re-find (re-pattern "\\d+") "abc123def") "123" ;; If you want to construct a regex pattern dynamically at run time, ;; then you need to use re-pattern to convert a string to a pattern ;; that can be used for matching. But if your pattern is one you ;; write into the source code, it is more convenient to use the ;; #"pattern" syntax. The previous example can be written as follows. user=> (re-find #"\d+" "abc123def") "123" ;; Below are two examples that are equivalent in the patterns they ;; use, but the #"pattern" syntax helps significantly, because it lets ;; us avoid the requirement to escape every \ character with another \ ;; character. See the example with embedded comments below for more ;; detail on what the pattern matches. user=> (re-find #"\\\d+\s+\S+" "\\ it sh0uld match in \\5 here somewhere.") "\\5 here" user=> (re-find (re-pattern "\\\\\\d+\\s+\\S+") "\\ it sh0uld match in \\5 here somewhere.") "\\5 here" ;; If you want to embed (ignored) whitespace and comments from # ;; characters until end-of-line in your regex patterns, start the ;; pattern with (?x) user=> (re-find #"(?x) # allow embedded whitespace and comments \\ # backslash \d+ # one or more digits \s+ # whitespace \S+ # non-whitespace" "\\ it sh0uld match in \\5 here somewhere.") "\\5 here" ;; Other pattern flags like Java's DOTALL, MULTILINE and UNICODE_CASE ;; pattern matching modes, can be set by combining these embedded flags ;; (?d) Unix lines (only match \newline) ;; (?i) Case-insensitive ;; (?u) Unicode-aware Case ;; (?m) Multiline ;; (?s) Dot matches all (including newline) ;; (?x) Ignore Whitespace and comments user=> (re-seq #"(?ix) test #Case insensitive and comments allowed" "Testing,\n testing,\n 1 2 3") ("Test" "test")