zOs/REXX.O08/SCAN
/* copy scan begin ****************************************************
Scan: scan an input:
scanLine(m,ln) : begin scanning a single line (string)
scanRead??(m,ln): begin scanning all lines of an opened reader
scanAtEnd(m) : returns whether we reached end of input
scanLit(m,lit) : scan Literal lit if present or return 0
scanChar(m,n) : scan next n characters
scanName(m) : scan a name
ScanNat(m) : scan a natural number (without sign)
scanString(m,q): scan a String with quote q. (with doubble = 1)
scanVerify(m,c,o): verify(...,c,o,...)
scanKeyValue(m): scan a key = value clause (with spaces)
scanWord(m,u) : scan a space delimited word or a string,
if u=1 then uppercase non-strings
scanErr(m, txt): error with current scan location
m is an adress, to store our state
if a scan function succeeds, the scan posititon is moved
returns: true if scanned, false otherwise
m.m.tok ==> last token
m.m.val ==> last value for scanString/Word/KeyValue
m.key ==> key for scanKeyValue
m.m.pos ==> scan position
m.m.src ==> scan source
***********************************************************************/
scanIni: procedure expose m.
if m.scan.ini == 1 then
return
m.scan.ini = 1
m.scan.alfLC = 'abcdefghijklmnopqrstuvwxyz'
m.scan.alfUC = translate(m.scan.alfLC)
m.scan.alfa = m.scan.alfLC || m.scan.alfUC
m.scan.alfNum = m.scan.alfa || '0123456789'
return
endProcedure scanIni
scanReset: procedure expose m.
parse arg m, n1, np, co
m.m.tok = ''
m.m.val = ''
m.m.key = ''
m.m.read = ''
return scanOpts(m, n1, np, co)
endProcedure scanReset
scanOpts: procedure expose m.
parse arg m, m.m.scanName1, namePlus, m.m.scanComment
call scanIni
if m.m.scanName1 == '' then
m.m.scanName1 = m.scan.alfa
if namePlus == '' then
m.m.scanNameR = m.m.scanName1 || '0123456789'
else
m.m.scanNameR = m.m.scanName1 || namePlus
return m
endProcedure scanReset
/*--- begin scanning a single line -----------------------------------*/
scanSrc: procedure expose m.
parse arg m, m.m.src
m.m.atEnd = 1
m.m.pos = 1
return m
endProcedure scanSrc
/*--- return the next len characters ---------------------------------*/
scanLook: procedure expose m.
parse arg m, len
if len == '' then
return substr(m.m.src, m.m.pos)
else
return substr(m.m.src, m.m.pos,
, min(len, 1 + length(m.m.src) - m.m.pos))
endProcedure scanLook
/*--- scan the literal lit ------------------------------------------*/
scanLit: procedure expose m.
parse arg m
do ax=2 to arg()
if abbrev(substr(m.m.src, m.m.pos), arg(ax)) then do
m.m.tok = arg(ax)
m.m.pos = m.m.pos + length(arg(ax))
return 1
end
end
m.m.tok = ''
return 0
endProcedure scanLit
/*--- scan the next len characters -----------------------------------*/
scanChar: procedure expose m.
parse arg m, len
nx = 1 + length(m.m.src)
if len ^= '' then
nx = min(m.m.pos + len, nx)
m.m.tok = substr(m.m.src, m.m.pos, nx - m.m.pos)
m.m.pos = nx
return m.m.tok ^== ''
endProcedure scanChar
/*--- scan a string with quote char qu -------------------------------*/
scanString: procedure expose m.
parse arg m, prefs
m.m.tok = ''
bx = m.m.pos
if prefs = '' then do
qu = substr(m.m.src, bx, 1)
if pos(qu, "'""") < 1 then
return 0
ax = bx + 1
end
else do
do px=1 until abbrev(substr(m.m.src, bx), p1)
p1 = word(prefs, px)
if p1 = '' then
return 0
end
qu = right(p1, 1)
ax = bx + length(p1)
end
m.m.val = ''
do forever
qx = pos(qu, m.m.src, ax)
if qx < 1 then
return scanErr(m, 'ending Apostroph('qu') missing')
m.m.val = m.m.val || substr(m.m.src, ax, qx-ax)
if qx >= length(m.m.src) then
leave
else if substr(m.m.src, qx+1, 1) <> qu then
leave
ax = qx+2
m.m.val = m.m.val || qu
end
m.m.tok = substr(m.m.src, bx, qx+1-bx)
m.m.pos = qx+1
return 1
endProcedure scanString
/*--- scan a Name, first char in *.scanName1, rest in *.scanNameR ----*/
scanName: procedure expose m.
parse arg m
if pos(substr(m.m.src, m.m.pos, 1),
, m.m.scanName1) <= 0 then do
m.m.tok = ''
return 0
end
return scanVerify(m, m.m.scanNameR)
endProcedure scanName
/*--- scan with verify, vOpt is passed to verify ---------------------*/
scanVerify: procedure expose m.
parse arg m, alpha, vOpt
if vOpt == '' then /* empty string does not take default| */
nx = verify(m.m.src, alpha, , m.m.pos)
else
nx = verify(m.m.src, alpha, vOpt, m.m.pos)
if nx = 0 then
nx = length(m.m.src) + 1
m.m.tok = substr(m.m.src, m.m.pos, nx - m.m.pos)
m.m.pos = nx
return m.m.tok ^== ''
endProcedure scanVerify
/*--- scan a natural number (no sign, decpoint ...) ------------------*/
scanNat: procedure expose m.
parse arg m, chEn
if ^ scanVerify(m, '0123456789') then
return 0
if chEn^==0 & pos(substr(m.m.src, m.m.pos,1), m.m.scanNameR)>0 then
call scanErr m, 'illegal number end'
return 1
endProcedure ScanNat
scanInt: procedure expose m.
parse arg m, chEn
if scanNat(m, chEn) then
return 1
ox = m.scan.m.pos
if pos(substr(m.scan.m.src, ox, 1) , '+-') < 1 then
return 0
m.scan.m.pos = ox + 1
if | scanNat(m) then do
m.scan.m.pos = ox
return 0
end
m.tok =substr(m.scan.m.src, ox, 1)|| m.tok
return 1
endProcedure scanInt
/*--- scan a word and put value into *.val
a word is either delimited by space or stopper
or a string (with single or double quotes -------*/
scanWord: procedure expose m.
parse arg m, stopper
if scanString(m) then return 1
if ^scanVerify(m, ' 'stopper, 'm') then return 0
m.m.val = m.m.tok
return 1
endProcedure scanWord
scanBack: procedure expose m.
parse arg m, tok
if m.m.pos <= length(tok) then
call scanErr sc, 'cannot back "'tok'" length'
cx = m.m.pos - length(tok)
if substr(m.m.src, cx, length(tok)) ^== tok then
call scanErr sc, 'cannot back "'tok'" value'
m.m.pos = cx
return
endProcedure scanBack
/*--- scan a key = word phrase
put key into m.key and word into m.m.val -------*/
scanKeyValue: procedure expose m.
parse arg m, def
if ^ scanName(m) then
return 0
m.m.key = m.m.tok
if ^ scanLit(scanSkip(m), '=') then do
m.m.val = def
m.m.tok = ' no='
end
else if ^scanWord(scanSkip(m)) then
call scanErr(m, 'word expected after' m.m.key '=')
return 1
endProcedure scanKeyValue
scanAtEnd: procedure expose m.
parse arg m
return m.m.atEnd & m.m.pos > length(m.m.src)
endProcedure scanAtEnd
/*--- skip over spaces, nl and comments (if option set) --------------*/
scanSpaceNL: procedure expose m.
parse arg m
lastTok = m.m.tok
if m.m.read ^== '' then
interpret 'res = ' oObjMethod(m, 'scanSpaceNl')
else
res = scanSpaceCom(m)
m.m.tok = lastTok
return res
endProcedure scanSpaceNL
scanSpaceCom: procedure expose m.
parse arg m
res = scanVerify(m, ' ')
if m.m.scanComment ^== '' then
if abbrev(substr(m.m.src, m.m.pos), m.m.scanComment) then do
m.m.pos = 1 + length(m.m.src)
return 1
end
return res
endProcedure scanSpaceCom
/*--- skip over space, nl and comments and return m -----------------*/
scanSkip: procedure expose m.
parse arg m
call scanSpaceNl m
return m
endProcedure scanSkip
/*--- emit an error with current scan pos ----------------------------*/
scanErr: procedure expose m.
parse arg m, txt
m.m.err.0 = 0
call err 'scanErr' txt'\n'scanInfo(m, m'.ERR')
return 0
endProcedure scanErr
scanPos: procedure expose m.
parse arg m
if m.m.read ^== '' then
interpret 'return' oObjMethod(m, 'scanPos')
else if scanAtEnd(m) then
return E
else
return 1 m.m.pos
endProcedure scanPos
scanInfo: procedure expose m.
parse arg m
msg = 'last token' m.m.tok 'scanPosition' ,
strip(left(substr(m.m.src, m.m.pos), 40), 't')
if m.m.read == '' then
return msg'\npos' m.m.Pos 'in string' strip(m.m.src, 't')
else
interpret 'return msg"\n" ||' oObjMethod(m, 'scanInfo')
endProcedure scanInfo
/* copy scan end ****************************************************/