Algol 68 - ACM Digital Library

104B)C)D)E)a)b)c)d)e)f)van Wijngaarden, et al.HEAD :: PLAIN ; PREF{71A} ; structured with ;FLEXETY ROWS of ; procedure with ; union of ; void.TAILETY :: MOlD ; FIELDS mode ; PARAMETERS yielding MOlD ;MOODS mode ; EMPTY.PARTS :: PART ; PARTS PART.PART :: FIELD ; PARAMETER.WHETHER MOIDI equivalent MOID2{64b,71m,72c} :WHETHER safe MOIDI equivalent safe MOII)2{b}.WHETHER SAFEI MOIDI equivalent SAFE2 MOID2{a,b,e,i,j,n} :where (SAFEI) contains (remember MOIDI MOLD2)or (SAFE2) contains (remember MOLD2 MOIDI),WHETHER true ;unless (SAFEI) contains (remember MOIDI MOLD2)or (SAFE2) contains (remember MOLD2 MOiDI),WHETHER (HEAD3) is (HEAD4)and remember MOIDI MOLD2 SAFE3 TAILETY3equivalent SAFE4 TAILETY4{b,d,e,k,q,-},where SAFE3 HEAD3 TAILETY3 develops fromSAFEI MOIDI{c}and SAFE4 HEAD4 TAILETY4 develops fromSAFE2 MOID2{c}.WHETHER SAFE2 HEAD TAILETY develops fromSAFEI MOID{b,e} :where (MOLD) is (HEAD TAILETY),WHETHER (HEAD) shields SAFEI to SAFE2{74a,b,e,d,-} ;where (MOLD) is (MU definition of MODE),unless (SAFEI) contains (MU has),WHETHER SAFE2 HEAD TAILETY develops fromMU has MODE SAFEI MODE{c} ;where (MOLD) is (MU application)and (SAFEI) is (NOTION MU has MODE SAFE3)and (NOTION) contains (yin) and (NOTION) contains (yang),WHETHER SAFE2 HEAD TAILETY develops fromSAFEI MODE{e}.WHETHER SAFEI FIELDSI modeequivalent SAFE2 FIELDS2 mode{b} :WHETHER SAFEI FIELDSI equivalent SAFE2 FIELDS2{f,g,h,i}.WHETHER SAFEI PARAMETERSI yielding MOLD!equivalent SAFE2 PARAMETERS2 yielding MOID2{b} :WHETHER SAFEI PARAMETERSIequivalent SAFE2 PARAMETERS2{f,g,h,j}and SAFEI MOIDI equivalent SAFE2 MOII)2{b}.WHETHER SAFE1 PARTSI PARTIequivalent SAFE2 PARTS2 PART2{d,e,f} :WHETHER SAFEI PARTSI equivalent SAFE2 PARTS2{f,g,h,i,j]and SAFE1 PARTI equivalent SAFE2 PART2{i,j}.g)b)i)J)k)m)n)o)p)ALGOL 68 Revised ReportWHETHER SAFEI PARTSI PARTI equivalentSAFE2 PART2{d,e,f} : WHETHER false.WHETHER SAFEI PARTI equivalentSAFE2 PARTS2 PART2{d,e,f} : WHETHER false.WHETHER SAFEI MODEl field TAGIequivalent SAFE2 MODE2 field TAG2{d,f} :WHETHER (TAGI) is (TAG2)and SAFEI MODEl equivalent SAFE2 MOI)E2{b}.WHETHER SAFEI MODEl parameterequivalent SAFE2 MODE2 parameter{e,f} :WHETHER SAFEI MODEl equivalent SAFE2 MODE2{b}.WHETHER SAFEI MOODS1 mode equivalentSAFE2 MOODS2 mode{b} :WHETHER SAFEI MOODSI subset of SAFE2 MOOI)S2{I,m,n}and SAFE2 MOODS2 subset of SAFEI MOOI)SI{l,m,n}and MOODSI number equals MOOI)S2 number{o,p}.WHETHER SAFEI MOODSI MOODIsubset of SAFE2 MOODS2{k,l,46s,64b} :WHETHER SAFEI MOODSI subset of SAFE2 MOODS2{1,m,n}and SAFEI MOODI subset of SAFE2 MOODS2{m,n}.WHETHER SAFEI MOODIsubset of SAFE2 MOODS2 MOOD2{k,l,m,46s,64b} :WHETHER SAFEI MOODI subset of SAFE2 MOODS2{m,n}or SAFEI MOODI subset of SAFE2 MOOD2{n}.WHETHER SAFEI MOODI subset of SAFE2 MOOD2{k,l,m,64b} :WHETHER SAFEI MOODI equivalent SAFE2 MOOD2{b}.WHETHER MOODSI MOODI number equalsMOODS2 MOOD2 number{k,o} :WHETHER MOODSI number equals MOODS2 number{o,p,-}.WHETHER MOODI number equals MOOD2 number{k,o} :WHETHER true.q) WHETHER SAFEI EMPTY equivalent SAFE2 EMPTY{b} :WHETHER true.{Rule a introduces the "SAFE's which are used as associative memoriesduring the determination of equivalence. There are two of them, onebelonging to each mode. Rule b draws an immediate conclusion if the'MOlD's under consideration are already remembered (see below) in anappropriate 'SAFE' in the form 'remember MOIDI MOLD2". If this is notthe case, then the two 'MOlD's are first remembered in a 'SAFE" (the oneon the left) and then each "MOLD" is developed (rule c) and split into its"HEAD' and its 'TAILETY', e.g., 'reference to real' is split into referenceto" and 'real'.if the 'HEAD's differ, then the matter is settled (rule b): otherwise the'TAILETY's are analyzed according to their structure (which must be thesame if the "HEAD's are identical). In each case, except where the105