50_a_history_of_qed
The current implementation of regular expressions in Bell Labs research software uses algorithms close to those in Ken 's CTSS and Multics versions , particularly the latter , because they do n't try to compile to machine code .

%3 0050_0001__The_0050_0003__implementation the_implementation 0050_0002__current current 0050_0001__The_0050_0003__implementation->0050_0002__current [attrib] 0050_0006__expressions expressions 0050_0001__The_0050_0003__implementation->0050_0006__expressions of 0050_0010__research_0050_0011__software research_software 0050_0001__The_0050_0003__implementation->0050_0010__research_0050_0011__software in 0050_0005__regular regular 0050_0006__expressions->0050_0005__regular [attrib] 0050_0008__Bell_0050_0009__Labs bell_labs 0050_0010__research_0050_0011__software->0050_0008__Bell_0050_0009__Labs [nlyr] 0050_0012__uses uses 0050_0012__uses->0050_0001__The_0050_0003__implementation [arg0] 0050_0013__algorithms algorithms 0050_0012__uses->0050_0013__algorithms [arg1] 0050_0014__close close 0050_0013__algorithms->0050_0014__close [attrib] 0050_0016__those those 0050_0014__close->0050_0016__those to 0050_0023__versions versions 0050_0016__those->0050_0023__versions in 0050_0021__and and 0050_0023__versions->0050_0021__and [nlyr] 0050_0018__Ken ken 0050_0023__versions->0050_0018__Ken [genv] 0050_0020__CTSS ctss 0050_0021__and->0050_0020__CTSS [conj1] 0050_0022__Multics multics 0050_0021__and->0050_0022__Multics [conj2] 0050_0026__the the 0050_0026__the->0050_0023__versions [prn] 0050_0025__particularly particularly 0050_0026__the->0050_0025__particularly [qual] 0050_0027__latter latter 0050_0026__the->0050_0027__latter [attrib] 0050_0029__because because[cnt] 0050_0029__because->0050_0012__uses [scope] 0050_0032__n't n't 0050_0029__because->0050_0032__n't [restriction] 0050_0033__try try 0050_0032__n't->0050_0033__try [scope] 0050_0035__compile compile 0050_0033__try->0050_0035__compile [arg1] 0050_0037__machine_0050_0038__code machine_code 0050_0035__compile->0050_0037__machine_0050_0038__code to[dir]
arc(r_0050_0001__The_r_0050_0003__implementation,r_0050_0002__current,attrib).
arc(r_0050_0001__The_r_0050_0003__implementation,r_0050_0006__expressions,r_0050_0004__of).
arc(r_0050_0001__The_r_0050_0003__implementation,r_0050_0010__research_r_0050_0011__software,r_0050_0007__in).
arc(r_0050_0006__expressions,r_0050_0005__regular,attrib).
arc(r_0050_0010__research_r_0050_0011__software,r_0050_0008__Bell_r_0050_0009__Labs,nlyr).
arc(r_0050_0012__uses,r_0050_0001__The_r_0050_0003__implementation,arg0).
arc(r_0050_0012__uses,r_0050_0013__algorithms,arg1).
arc(r_0050_0013__algorithms,r_0050_0014__close,attrib).
arc(r_0050_0014__close,r_0050_0016__those,r_0050_0015__to).
arc(r_0050_0016__those,r_0050_0023__versions,r_0050_0017__in).
arc(r_0050_0021__and,r_0050_0020__CTSS,conj1).
arc(r_0050_0021__and,r_0050_0022__Multics,conj2).
arc(r_0050_0023__versions,r_0050_0018__Ken,genv).
arc(r_0050_0023__versions,r_0050_0021__and,nlyr).
arc(r_0050_0026__the,r_0050_0023__versions,prn).
arc(r_0050_0026__the,r_0050_0025__particularly,qual).
arc(r_0050_0026__the,r_0050_0027__latter,attrib).
arc(r_0050_0029__because_cnt,r_0050_0012__uses,scope_).
arc(r_0050_0029__because_cnt,r_0050_0032__n_apos_t,restriction_).
arc(r_0050_0032__n_apos_t,r_0050_0033__try,keep_scope).
arc(r_0050_0033__try,r_0050_0035__compile,arg1).
arc(r_0050_0035__compile,r_0050_0037__machine_r_0050_0038__code,r_0050_0036__to__dir).


IP-MAT NP-SBJ D The ADJP ADJ current N implementation PP P-ROLE of NP ADJP ADJ regular NS expressions PP P-ROLE in NP NLYR NPR Bell NPR Labs N research N software VBP uses NP-OB1 NS algorithms ADJP ADJ close PP P-ROLE to NP D;_nphd_ those PP P-ROLE in NP NP-GENV NPR Ken GENM 's NLYR NLYR NP NPR CTSS CONJP CONJ and NP NPR Multics NS versions PUNC , PRN NP ADVP ADV particularly D the ADJP ADJ latter PUNC , PP-SCON-CNT P-CONN because IP-ADV NP PRO they DOP do NEG;_clitic_ n't VB try IP-INF-OB1 TO to VB compile PP-DIR P-ROLE to NP N machine N code PUNC .
( (IP-MAT (NP-SBJ (D The;{the})
                  (ADJP (ADJ current;{current}))
                  (N implementation;{implementation})
                  (PP (P-ROLE of;{of})
                      (NP;{CURRENT_REGEX} (ADJP (ADJ regular;{regular}))
                                          (NS expressions;{expression})))
                  (PP (P-ROLE in;{in})
                      (NP (NLYR (NPR Bell;{Bell})
                                (NPR Labs;{Labs}))
                          (N research;{research})
                          (N software;{software}))))
          (VBP uses;{use})
          (NP-OB1 (NS algorithms;{algorithm})
                  (ADJP (ADJ close;{close})
                        (PP (P-ROLE to;{to})
                            (NP (D;_nphd_ those;{those})
                                (PP (P-ROLE in;{in})
                                    (NP (NP-GENV;{KEN} (NPR Ken;{Ken})
                                                       (GENM <apos>s))
                                        (NLYR (NLYR (NP (NPR CTSS;{CTSS}))
                                                    (CONJP (CONJ and;{and})
                                                           (NP (NPR Multics;{Multics})))))
                                        (NS versions;{version})
                                        (PUNC ,)
                                        (PRN (NP (ADVP (ADV particularly;{particularly}))
                                                 (D the;{the})
                                                 (ADJP (ADJ latter;{latter}))))))))))
          (PUNC ,)
          (PP-SCON-CNT (P-CONN because;{because})
                       (IP-ADV (NP;{CURRENT_REGEX} (PRO they;{they}))
                               (DOP do;{do})
                               (NEG;_clitic_ n<apos>t;{not})
                               (VB try;{try})
                               (IP-INF-OB1 (TO to;{to})
                                           (VB compile;{compile})
                                           (PP-DIR (P-ROLE to;{to})
                                                   (NP (N machine;{machine})
                                                       (N code;{code}))))))
          (PUNC .))
  (ID 50_a_history_of_qed))