+++ title = "4i: Parsing (Useful Idioms)" weight = 36 template = "doc.html" +++ ### `++alf` Alphabetic characters Parse alphabetic characters, both upper and lowercase. #### Source ```hoon ++ alf ;~(pose low hig) :: alphabetic ``` #### Examples ``` > (scan "a" alf) ~~a > (scan "A" alf) ~~~41. > (scan "AaBbCc" (star alf)) "AaBbCc" ``` --- ### `++aln` Alphanumeric characters Parse alphanumeric characters - both alphabetic characters and numbers. #### Source ```hoon ++ aln ;~(pose low hig nud) :: alphanumeric ``` #### Examples ``` > (scan "0" aln) ~~0 > (scan "alf42" (star aln)) "alf42" > (scan "0123456789abcdef" (star aln)) "0123456789abcdef" ``` --- ### `++alp` Alphanumeric and `-` Parse alphanumeric strings and hep, "-". #### Source ```hoon ++ alp ;~(pose low hig nud hep) :: alphanumeric and - ``` #### Examples ``` > (scan "7" alp) ~~7 > (scan "s" alp) ~~s > (scan "123abc-" (star alp)) "123abc-" ``` --- ### `++bet` Axis syntax `-`, `+` Parse the hep and lus axis syntax. #### Source ```hoon ++ bet ;~(pose (cold 2 hep) (cold 3 lus)) :: axis syntax - + ``` #### Examples ``` > (scan "-" bet) 2 > (scan "+" bet) 3 ``` --- ### `++bin` Binary to atom Parse a tape of binary (0s and 1s) and produce its atomic representation. #### Source ```hoon ++ bin (bass 2 (most gon but)) :: binary to atom ``` #### Examples ``` > (scan "0000" bin) 0 > (scan "0001" bin) 1 > (scan "0010" bin) 2 > (scan "100000001111" bin) 2.063 ``` --- ### `++but` Binary digit Parse a single binary digit. #### Source ```hoon ++ but (cook |=(a=@ (sub a '0')) (shim '0' '1')) :: binary digit ``` #### Examples ``` > (scan "0" but) 0 > (scan "1" but) 1 > (scan "01" but) ! {1 2} ! 'syntax-error' ! exit > (scan "01" (star but)) ~[0 1] ``` --- ### `++cit` Octal digit Parse a single octal digit. #### Source ```hoon ++ cit (cook |=(a=@ (sub a '0')) (shim '0' '7')) :: octal digit ``` #### Examples ``` > (scan "1" cit) 1 > (scan "7" cit) 7 > (scan "8" cit) ! {1 1} ! 'syntax-error' ! exit > (scan "60" (star cit)) ~[6 0] ``` --- ### `++dem` Decimal to atom Parse a decimal number to an atom. #### Source ```hoon ++ dem (bass 10 (most gon dit)) :: decimal to atom ``` #### Examples ``` > (scan "7" dem) 7 > (scan "42" dem) 42 > (scan "150000000" dem) 150.000.000 > (scan "12456" dem) 12.456 ``` --- ### `++dit` Decimal digit Parse a single decimal digit. #### Source ```hoon ++ dit (cook |=(a=@ (sub a '0')) (shim '0' '9')) :: decimal digit ``` #### Examples ``` > (scan "7" dit) 7 > (scan "42" (star dit)) ~[4 2] > (scan "26000" (star dit)) ~[2 6 0 0 0] ``` --- ### `++dog` `.` optional gap Dot followed by an optional gap, used with numbers. #### Source ```hoon ++ dog ;~(plug dot gay) :: ``` #### Examples ``` > 1.234.703 703 1.234.703 > (scan "a. " ;~(pfix alf dog)) [~~~. ~] ``` --- ### `++doh` `@p` separator Phonetic base phrase separator #### Source ```hoon ++ doh ;~(plug ;~(plug hep hep) gay) :: ``` #### Examples ``` /> ~nopfel-botduc-nilnev-dolfyn--haspub-natlun-lodmur-holtyd ~nopfel-botduc-nilnev-dolfyn--haspub-natlun-lodmur-holtyd /> ~nopfel-botduc-nilnev-dolfyn-- haspub-natlun-lodmur-holtyd ~nopfel-botduc-nilnev-dolfyn--haspub-natlun-lodmur-holtyd > (scan "--" doh) [[~~- ~~-] ~] > (scan "-- " doh) [[~~- ~~-] ~] ``` --- ### `++dun` `--` to `~` Parse phep, `--`, to null, `~`. #### Source ```hoon ++ dun (cold ~ ;~(plug hep hep)) :: -- (phep) to ~ ``` #### Examples ``` > (scan "--" dun) ~ > (dun [[1 1] "--"]) [p=[p=1 q=3] q=[~ u=[p=~ q=[p=[p=1 q=3] q=""]]]] ``` --- ### `++duz` `==` to `~` Parse stet, `==`, to null `~`. #### Source ```hoon ++ duz (cold ~ ;~(plug tis tis)) :: == (stet) to ~ ``` #### Examples ``` > (scan "==" duz) ~ > (duz [[1 1] "== |=..."]) [p=[p=1 q=3] q=[~ u=[p=~ q=[p=[p=1 q=3] q=" |=..."]]]] ``` --- ### `++gah` Newline or ' ' Whitespace component, either newline or space. #### Source ```hoon ++ gah (mask [`@`10 ' ' ~]) :: newline or ace ``` #### Examples ``` /> ^- * :: show spaces """ - - - """ [32 32 32 45 10 32 45 10 32 32 45 0] /> ^- * """ """ [32 32 32 10 32 10 32 32 0] /> ^- (list ,@) %- scan :_ (star gah) """ """ ~[32 32 32 10 32 10 32 32] ``` --- ### `++gap` Plural whitespace Separates tall runes #### Source ```hoon ++ gap (cold ~ ;~(plug gaq (star ;~(pose vul gah)))) :: plural whitespace ``` --- ### `++gaq` End of line Two spaces, a newline, or comment. #### Source ```hoon ++ gaq ;~ pose :: end of line (just `@`10) ;~(plug gah ;~(pose gah vul)) vul == ``` --- ### `++gaw` Classic whitespace Terran whitespace. #### Source ```hoon ++ gaw (cold ~ (star ;~(pose vul gah))) :: classic white ``` --- ### `++gay` Optional gap Optional gap. #### Source ```hoon ++ gay ;~(pose gap (easy ~)) :: ``` --- ### `++gon` Long numbers Parse long numbers - Numbers which wrap around the shell with the line #### Source ```hoon ++ gon ;~(pose ;~(plug bas gay fas) (easy ~)) :: long numbers \ / ``` #### Examples ``` > (scan "\\/" gon) [~~~5c. ~ ~~~2f.] > (gon [[1 1] "\\/"]) [p=[p=1 q=3] q=[~ u=[p=[~~~5c. ~ ~~~2f.] q=[p=[p=1 q=3] q=""]]]] ``` --- ### `++gul` Axis syntax `<` or `>` Parse the axis gal and gar axis syntax. #### Source ```hoon ++ gul ;~(pose (cold 2 gal) (cold 3 gar)) :: axis syntax < > ``` #### Examples ``` > (scan "<" gul) 2 > (scan ">" gul) 3 ``` --- ### `++hex` Hex to atom Parse any hexadecimal number to an atom. #### Source ```hoon ++ hex (bass 16 (most gon hit)) :: hex to atom ``` #### Examples ``` > (scan "a" hex) 10 > (scan "A" hex) 10 > (scan "2A" hex) 42 > (scan "1ee7" hex) 7.911 > (scan "1EE7" hex) 7.911 > (scan "1EE7F7" hex) 2.025.463 > `@ux`(scan "1EE7F7" hex) 0x1e.e7f7 ``` --- ### `++hig` Uppercase Parse a single uppercase letter. #### Source ```hoon ++ hig (shim 'A' 'Z') :: uppercase ``` #### Examples ``` > (scan "G" hig) ~~~47. > `cord`(scan "G" hig) 'G' > (scan "ABCDEFGHIJKLMNOPQRSTUVWXYZ" (star hig)) "ABCDEFGHIJKLMNOPQRSTUVWXYZ" > (hig [[1 1] "G"]) [p=[p=1 q=2] q=[~ [p=~~~47. q=[p=[p=1 q=2] q=""]]]] ``` --- ### `++hit` Hex digits Parse a single hexadecimal digit. #### Source ```hoon ++ hit ;~ pose :: hex digits dit (cook |=(a=char (sub a 87)) (shim 'a' 'f')) (cook |=(a=char (sub a 55)) (shim 'A' 'F')) == ``` #### Examples ``` > (scan "a" hit) 10 > (scan "A" hit) 10 > (hit [[1 1] "a"]) [p=[p=1 q=2] q=[~ [p=10 q=[p=[p=1 q=2] q=""]]]] > (scan "2A" (star hit)) ~[2 10] ``` --- ### `++iny` Indentation block Apply `++rule` to indented block starting at current column number, omitting the leading whitespace. #### Accepts `sef` is a `++rule` #### Produces A `++rule`. #### Source ```hoon ++ inde |* sef/rule :: indentation block |= nail ^+ (sef) =+ [har tap]=[p q]:+< =+ lev=(fil 3 (dec q.har) ' ') =+ eol=(just `@t`10) =+ =- roq=((star ;~(pose prn ;~(sfix eol (jest lev)) -)) har tap) ;~(simu ;~(plug eol eol) eol) ?~ q.roq roq =+ vex=(sef har(q 1) p.u.q.roq) =+ fur=p.vex(q (add (dec q.har) q.p.vex)) ?~ q.vex vex(p fur) =- vex(p fur, u.q -) :+ &3.vex &4.vex(q.p (add (dec q.har) q.p.&4.vex)) =+ res=|4.vex |- ?~ res |4.roq ?. =(10 -.res) [-.res $(res +.res)] (welp [`@t`10 (trip lev)] $(res +.res)) :: ``` #### Examples ``` > (scan "abc" (iny (star ;~(pose prn (just `@`10))))) "abc" > (scan "abc" (star ;~(pose prn (just `@`10)))) "abc" > (scan " abc\0ade" ;~(pfix ace ace (star ;~(pose prn (just `@`10))))) "abc de" > (scan " abc\0ade" ;~(pfix ace ace (iny (star ;~(pose prn (just `@`10)))))) ! {1 6} ! exit > (scan " abc\0a de" ;~(pfix ace ace (iny (star ;~(pose prn (just `@`10)))))) "abc de" ``` --- ### `++low` Lowercase Parse a single lowercase letter. #### Source ```hoon ++ low (shim 'a' 'z') :: lowercase ``` #### Examples ``` > (scan "g" low) ~~g > `cord`(scan "g" low) 'g' > (scan "abcdefghijklmnopqrstuvwxyz" (star low)) "abcdefghijklmnopqrstuvwxyz" > (low [[1 1] "g"]) [p=[p=1 q=2] q=[~ [p=~~g q=[p=[p=1 q=2] q=""]]]] ``` --- ### `++mes` Hexbyte Parse a hexbyte. #### Source ```hoon ++ mes %+ cook :: hexbyte |=({a/@ b/@} (add (mul 16 a) b)) ;~(plug hit hit) ``` #### Examples ``` > (scan "2A" mes) 42 > (mes [[1 1] "2A"]) [p=[p=1 q=3] q=[~ u=[p=42 q=[p=[p=1 q=3] q=""]]]] > (scan "42" mes) 66 ``` --- ### `++nix` Letters and `-` Parse Letters and `-`. #### Source ```hoon ++ nix (boss 256 (star ;~(pose aln cab))) :: ``` #### Examples ``` > (scan "as_me" nix) q=435.626.668.897 > `@t`(scan "as_me" nix) 'as_me' ``` --- ### `++nud` Numeric Parse a numeric character - A number. #### Source ```hoon ++ nud (shim '0' '9') :: numeric ``` #### Examples ``` > (scan "0" nud) ~~0 > (scan "7" nud) ~~7 > (nud [[1 1] "1"]) [p=[p=1 q=2] q=[~ [p=~~1 q=[p=[p=1 q=2] q=""]]]] > (scan "0123456789" (star nud)) "0123456789" ``` --- ### `++prn` Printable character Parse any printable character. #### Source ```hoon ++ prn ;~(less (just `@`127) (shim 32 256)) ``` #### Examples ``` > (scan "h" prn) ~~h > (scan "!" prn) ~~~21. > (scan "\01" prn) ! {1 1} ! exit ``` --- ### `++qit` Chars in cord Parse an individual character to its cord atom representation. #### Source ```hoon ++ qit ;~ pose :: chars in a cord ;~(less bas soq prn) ;~(pfix bas ;~(pose bas soq mes)) :: escape chars == ``` #### Examples ``` > (scan "%" qit) 37 > `@t`(scan "%" qit) '%' > (scan "0" qit) 48 > (scan "E" qit) 69 > (scan "a" qit) 97 > (scan "\\0a" qit) 10 > `@ux`(scan "\\0a" qit) 0xa > (scan "cord" (star qit)) ~[99 111 114 100] ``` --- ### `++qit` Chars in cord Parse an individual character to its cord atom representation. #### Source ```hoon ++ qit ;~ pose :: chars in a cord ;~(less bas soq prn) ;~(pfix bas ;~(pose bas soq mes)) :: escape chars == ``` #### Examples ``` > (scan "%" qit) 37 > `@t`(scan "%" qit) '%' > (scan "0" qit) 48 > (scan "E" qit) 69 > (scan "a" qit) 97 > (scan "\\0a" qit) 10 > `@ux`(scan "\\0a" qit) 0xa > (scan "cord" (star qit)) ~[99 111 114 100] ``` --- ### `++qut` Cord Parse single-soq cord with `\{gap}/` anywhere in the middle, or triple-single quote (aka triple-soq) cord, between which must be in an indented block. #### Source ```hoon ++ qut ;~ pose :: cord ;~ less soqs (ifix [soq soq] (boss 256 (more gon qit))) == %- inde %+ ifix :- ;~ plug soqs ;~(pose ;~(plug (plus ace) vul) (just '\0a')) == ;~(plug (just '\0a') soqs) (boss 256 (star qat)) == :: ``` #### Examples ``` > (scan "'cord'" qut) q=1.685.221.219 > 'cord' 'cord' > `@ud`'cord' 1.685.221.219 > ''' Heredoc isn't prohibited from containing quotes ''' 'Heredoc isn't prohibited from containing quotes' ``` --- ### `++soz` Delimiting `'''` Parse a triple-single quote, used for multiline strings. #### Source ```hoon ++ soz ;~(plug soq soq soq) :: delimiting ''' ``` #### Examples ``` > (scan "'''" soz) [~~~27. ~~~27. ~~~27.] > (rash '"""' soz) ! {1 1} ! exit ``` --- ### `++sym` Term A term: a letter(lowercase), followed by letters, numbers, or `-`. #### Source ```hoon ++ sym %+ cook |=(a=tape (rap 3 ^-((list ,@) a))) ;~(plug low (star ;~(pose nud low hep))) :: ``` #### Examples ``` > (scan "sam-2" sym) 215.510.507.891 > `@t`(scan "sam-2" sym) 'sam-2' > (scan "sym" sym) 7.174.515 ``` --- ### `++ven` `+>-` axis syntax Axis syntax parser #### Source ```hoon ++ ven ;~ (comp |=({a/@ b/@} (peg a b))) :: +>- axis syntax bet =+ hom=`?`| |= tub/nail ^- (like axis) =+ vex=?:(hom (bet tub) (gul tub)) ?~ q.vex [p.tub [~ 1 tub]] =+ wag=$(p.tub p.vex, hom !hom, tub q.u.q.vex) ?> ?=(^ q.wag) [p.wag [~ (peg p.u.q.vex p.u.q.wag) q.u.q.wag]] == ``` #### Examples ``` ~zod/arvo=/hoon/hoon> (scan "->+" ven) 11 ~zod/arvo=/hoon/hoon> `@ub`(scan "->+" ven) 0b1011 ~zod/arvo=/hoon/hoon> (peg (scan "->" ven) (scan "+" ven)) 11 ~zod/arvo=/hoon/hoon> ->+:[[1 2 [3 4]] 5] [3 4] ``` --- ### `++vit` Base64 digit Parse a standard base64 digit. #### Source ```hoon ++ vit :: base64 digit ;~ pose (cook |=(a/@ (sub a 65)) (shim 'A' 'Z')) (cook |=(a/@ (sub a 71)) (shim 'a' 'z')) (cook |=(a/@ (add a 4)) (shim '0' '9')) (cold 62 (just '-')) (cold 63 (just '+')) == ``` #### Examples ``` ~zod/arvo=/hoon/hoon> (scan "C" vit) 2 ~zod/arvo=/hoon/hoon> (scan "c" vit) 28 ~zod/arvo=/hoon/hoon> (scan "2" vit) 54 ~zod/arvo=/hoon/hoon> (scan "-" vit) 62 ``` --- ### `++vul` Comments to null #### Source ```hoon ++ vul %+ cold ~ :: comments ;~ plug col col (star prn) (just `@`10) == ``` Parse comments and produce a null. Note that a comment must be ended with a newline character. #### Examples ``` > (scan "::this is a comment \0a" vul) ~ > (scan "::this is a comment " vul) ! {1 21} ! exit ``` ---