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Diffstat (limited to 'sys/fmtio/doc/lexnum.hlp')
| -rw-r--r-- | sys/fmtio/doc/lexnum.hlp | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/sys/fmtio/doc/lexnum.hlp b/sys/fmtio/doc/lexnum.hlp new file mode 100644 index 00000000..647654b1 --- /dev/null +++ b/sys/fmtio/doc/lexnum.hlp @@ -0,0 +1,303 @@ + +.help lexnum 2 "string utilities" +.ih _________________________________________________________________________ +NAME +lexnum -- Determine if string is a number +.ih +USAGE +token_type = lexnum (str, ip, nchars) + +.ih +PARAMETERS +.ls str +String to be scanned. +.le +.ls ip +Index within the string as which scanning is to start. Not modified. +.le +.ls nchars +On output, the number of characters in the number, not including any +leading whitespace. +.le +.ih +DESCRIPTION +The character string is scanned to determine if the next token is a +legal number, and if so, the type of number. The function value identifies +the type of number. The possible return values, defined in <lexnum.h>, +as as follows: + +.nf + LEX_OCTAL (+|-)?[0-7]+[bB] + LEX_DECIMAL (+|-)?[0-9]+ + LEX_HEX (+|-)?[0-9a-fA-F]+[xX] + LEX_REAL floating, exponential [eEdD], sexagesimal + LEX_NONNUM not a number +.fi +.ih +IMPLEMENTATION +Numtype is implemented as a finite state automaton. Additional documentation +is provided with the source code. +.ih +SEE ALSO +gctod(2), ctotok(2). +.endhelp ___________________________________________________________________ + + + +.help states 2 "States of the LEXNUM Finite State Automaton" +.fi + + +.ks +.nf +start: (1) + +- shift unop_or_number + 0-7 shift odhr + 8-9 shift dhr + acf reduce not_a_number + ed reduce not_a_number + : shift maybe_real_number + . shift maybe_real_fraction + x reduce not_a_number + b reduce not_a_number + other reduce not_a_number +.fi +.ke + + +.ks +.nf +unop_or_number: (+|-) (2) + +- revert + 0-7 shift odhr + 8-9 shift dhr + acf revert + ed revert + : revert + . shift maybe_real_fraction + x revert + b revert + other revert +.fi +.ke + + +.ks +.nf +odhr: (+|-)?[0-7] (3) + +- reduce decimal_number + 0-7 accept + 8-9 shift dhr + acf shift h + ed shift maybe_hex_or_rexp + : shift maybe_real_number + . shift real_fraction + x reduce hex_number + b shift octal_or_hex_number + other reduce decimal_number +.fi +.ke + + +.ks +.nf +dhr: (+|-)?[0-9]+ (4) + +- reduce decimal_number + 0-7 accept + 8-9 accept + acf shift h + ed shift maybe_hex_or_rexp + : shift maybe_real_number + . shift real_fraction + x reduce hex_number + b shift h + other reduce decimal_number +.fi +.ke + + +.ks +.nf +maybe_real_fraction: (+|-)?"." (5) + +- revert + 0-7 shift real_fraction + 8-9 shift real_fraction + acf revert + ed revert + : revert + . revert + x revert + b revert + other revert +.fi +.ke + + +.ks +.nf +h: (+|-)?[0-9]*[a-f] (6) + +- revert + 0-7 accept + 8-9 accept + acf accept + ed accept + : revert + . revert + x reduce hex_number + b accept + other revert +.fi +.ke + + +.ks +.nf +maybe_hex_or_rexp: (+|-)?[0-9]+[ed] (7) + +- shift maybe_rexp + 0-7 shift hex_or_rexp + 8-9 shift hex_or_rexp + acf shift h + ed shift h + : revert + . revert + x reduce hex_number + b shift h + other revert +.fi +.ke + + +.ks +.nf +maybe_real_number: (+|-)?[0-9]*":" (8) + +- revert + 0-7 shift r + 8-9 shift r + acf revert + ed revert + : accept + . revert + x revert + b revert + other revert +.fi +.ke + + +.ks +.nf +octal_or_hex_number: (+|-)?[0-7]"b" (9) + +- reduce octal_number + 0-7 shift h + 8-9 shift h + acf shift h + ed shift h + : reduce octal_number + . reduce octal_number + x reduce hex_number + b shift h + other reduce octal_number +.fi +.ke + + +.ks +.nf +real_fraction: (+|-)?"."[0-9] (10) + +- reduce real_number + 0-7 accept + 8-9 accept + acf reduce real_number + ed shift rfr_or_rexp + : reduce real_number + . reduce real_number + x reduce real_number + b reduce real_number + other reduce real_number +.fi +.ke + + +.ks +.nf +rfr_or_rexp: (+|-)?"."[0-9]+[ed] (11) + +- shift maybe_rexp + 0-7 shift rexp + 8-9 shift rexp + acf revert + ed revert + : revert + . revert + x revert + b revert + other revert +.fi +.ke + + +.ks +.nf +maybe_rexp: (+|-)?[0-9]+[ed](+|-) (12) + +- revert + 0-7 shift rexp + 8-9 shift rexp + acf revert + ed revert + : revert + . revert + x revert + b revert + other revert +.fi +.ke + + +.ks +.nf +hex_or_rexp: (+|-)?[0-9]+[ed][0-9] (13) + +- reduce real_number + 0-7 accept + 8-9 accept + acf shift h + ed shift h + : reduce real_number + . reduce real_number + x reduce hex_number + b reduce real_number + other reduce real_number +.fi +.ke + + +.ks +.nf +r: (+|-)?[0-9]*":"[0-9] (14) + +- reduce real_number + 0-7 accept + 8-9 accept + acf reduce real_number + ed shift maybe_rexp + : accept + . shift maybe_real_fraction + x reduce real_number + b reduce real_number + other reduce real_number +.fi +.ke + + +.ks +.nf +rexp: (+|-)?[0-9]+[ed](+|-)[0-9] (15) + +- reduce real_number + 0-7 accept + 8-9 accept + acf reduce real_number + ed reduce real_number + : reduce real_number + . reduce real_number + x reduce real_number + b reduce real_number + other reduce real_number +.fi +.ke |