zOs/REXX.O08/SCAN1
/* copy scan begin ****************************************************
Scan: scan an input:
scanLine(m,ln) : begin scanning a single line
scanStem(m,ln) : begin scanning all lines in a stem
scanAtEOL(m) : returns whether we reached end of line
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
scanNum(m) : scan integer (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.tok ==> last token
m.val ==> last value for scanString/Word/KeyValue
m.key ==> key for scanKeyValue
m.scan.m.pos ==> scan position
m.scan.m.src ==> scan source
***********************************************************************/
/*--- begin scanning a single line -----------------------------------*/
scanLine: procedure expose m.
parse arg m, m.scan.m.src
call scanStart m
return
endProcedure scanLine
/*--- begin scanning the lines of a stem -----------------------------*/
scanReader: procedure expose m.
parse arg m, inRdr
call scanStart m, inRdr
m.scan.m.src = ''
m.scan.m.atEnd = ^ scanNL(m, 1)
return m
endProcedure scanReader
/*--- switch to next line if atEOF or argument unCond=1 --------------*/
scanNL: procedure expose m.
parse arg m, unCond
if unCond == 1 then
m.scan.m.pos = 1 + length(m.scan.m.src)
else if m.scan.m.pos <= length(m.scan.m.src) then
return 0
if m.scan.m.reader = '' then
return 0
else if ^ ooRead(m.scan.m.reader, 'SCAN.'m'.SRC') then do
m.scan.m.atEnd = 1
return 0
end
m.scan.m.pos = 1
m.scan.m.tok = ''
return 1
endProcedure scanNL
/*--- initialize scanner for m --------------------------------------*/
scanStart: procedure expose m.
parse arg m, m.scan.m.reader
m.scan.m.pos = 1
m.tok = ''
m.val = ''
m.key = ''
if symbol('m.scan.m.Name') ^== 'VAR' then do
m.scan.LC = 'abcdefghijklmnopqurstuvwxyz'
m.scan.UC = 'ABCDEFGHIJKLMNOPQURSTUVWXYZ'
m.scan.Alpha = m.scan.LC || m.scan.UC
m.scan.AlNum = '0123456789' || m.scan.ALPHA
m.scan.m.Name1 = m.scan.ALPHA
m.scan.m.Name = m.scan.ALNUM
m.scan.m.comment = ''
end
return
endProcedure scanStart
/*--- set options name characters, comment characters ----------------*/
scanOptions: procedure expose m.
parse arg m, nameOne, namePlus, comm
if symbol('m.scan.m.Name') ^== 'VAR' then
call scanStart
if nameOne ^== '' then do
m.scan.m.Name1 = nameOne
if namePlus = '' then
namePlus = '0123456789'
m.scan.m.name = nameOne || namePlus
end
m.scan.m.comment = comm
return
endProcedure scanBegin
/*--- return true/false whether we are at the end of the line --------*/
scanAtEOL: procedure expose m.
parse arg m
return m.scan.m.pos > length(m.scan.m.src)
endProcedure scanAtEOL
/*--- return true/false whether we are at the end of the input -------*/
scanAtEnd: procedure expose m.
parse arg m
if m.scan.m.pos <= length(m.scan.m.src) then
return 0
if m.scan.m.reader = '' then
return 1
else
return m.scan.m.atEnd
endProcedure scanAtEnd
/*--- scan len characters --------------------------------------------*/
scanChar: procedure expose m.
parse arg m, len
nx = 1 + length(m.scan.m.src)
if len ^== '' then
if nx > m.scan.m.pos + len then
nx = m.scan.m.pos + len
m.tok = substr(m.scan.m.src, m.scan.m.pos, nx - m.scan.m.pos)
if nx = m.scan.m.pos then
return 0
m.scan.m.pos = nx
return 1
endProcedure scanChar
/*--- scan the literal lit ------------------------------------------*/
scanLit: procedure expose m.
parse arg m, lit
if ^ abbrev(substr(m.scan.m.src, m.scan.m.pos), lit) then
return 0
m.scan.m.pos = m.scan.m.pos + length(lit)
m.tok = lit
return 1
endProcedure scanLit
/*--- scan a string with quote char qu -------------------------------*/
scanString: procedure expose m.
parse arg m, qu
m.val = ''
if qu = '' then
qu = "'"
if substr(m.scan.m.src, m.scan.m.pos, 1) ^== qu then
return 0
bx = m.scan.m.pos
qx = m.scan.m.pos + 1
do forever
px = pos(qu, m.scan.m.src, qx)
if px < 1 then
call scanErr m, 'ending Apostroph('qu') missing'
m.val = m.val || substr(m.scan.m.src, qx, px-qx)
if px >= length(m.scan.m.src) then
leave
else if substr(m.scan.m.src, px+1, 1) <> qu then
leave
qx = px+2
m.val = m.val || qu
end
m.tok = substr(m.scan.m.src, bx, px+1-bx)
m.scan.m.pos = px+1
return 1
endProcedure scanString
/*--- scan a Name, first char in *.name1, rest in *.name -------------*/
scanName: procedure expose m.
parse arg m
if pos(substr(m.scan.m.src, m.scan.m.pos, 1),
, m.scan.m.Name1) <= 0 then
return 0
bx = m.scan.m.pos
m.scan.m.pos = bx + 1
call scanVerify m, m.scan.m.Name
m.tok = substr(m.scan.m.src, bx, m.scan.m.pos - bx)
return 1
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.scan.m.src, alpha, , m.scan.m.pos)
else
nx = verify(m.scan.m.src, alpha, vOpt, m.scan.m.pos)
if nx = 0 then
nx = length(m.scan.m.src) + 1
m.tok = substr(m.scan.m.src, m.scan.m.Pos, nx - m.scan.m.Pos)
if nx <= m.scan.m.pos then
return 0
m.scan.m.pos = nx
return 1
endProcedure scanVerify
/*--- scan a number --------------------------------------------------*/
scanNum: procedure expose m.
parse arg m
if ^ scanVerify(m, '0123456789') then
return 0
else if pos(substr(m.scan.m.src, m.scan.m.pos, 1), m.scan.m.name1) ,
> 0 then
call scanErr m, 'illegal number end'
return 1
endProcedure scanNum
/*--- 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 scanString(m, """") then return 1
if ^scanVerify(m, ' 'stopper, 'm') then return 0
m.val = m.tok
return 1
endProcedure scanWord
scanBack: procedure expose m.
parse arg m, tok
if m.scan.m.pos <= length(tok) then
call scanErr sc, 'cannot back "'tok'" length'
cx = m.scan.m.pos - length(tok)
if substr(m.scan.m.src, ix, length(tok) ^== tok then
call scanErr sc, 'cannot back "'tok'" value'
m.scan.m.pos = cx
return
endProcedure scanBack
/*--- scan a key = word phrase
put key into *.key and word into val -------*/
scanKeyValue: procedure expose m.
parse arg m, def
if ^ scanName(scanSkip(m)) then
return 0
m.key = m.tok
if ^ scanLit(scanSkip(m), '=') then do
m.val = def
m.tok = ' no='
end
else if ^scanWord(scanSkip(m)) then
call scanErr(m, 'word expected after' m.key '=')
return 1
endProcedure scanKeyValue
/*--- emit an error with current scan pos ----------------------------*/
scanErr: procedure expose m.
parse arg m, txt
say 'scanErr' txt
say ' last token' m.tok
say ' charPos' m.scan.m.Pos':',
strip(substr(m.scan.m.src, m.scan.m.Pos), 't')
say ' in line:' strip(m.scan.m.src, 't')
call err 'scanErr' txt
endProcedure scanErr
/*--- skip over spaces, nl and comments (if option set) --------------*/
scanSpaceNL: procedure expose m.
parse arg m
lastTok = m.tok
res = 0
cc = m.scan.m.comment
do forever
if scanVerify(m, ' ') then nop
else if scanNL(m) then nop
else if cc == '' then leave
else if ^ scanLit(m, cc) then leave
else if ^scanNL(m, 1) then leave
res = 1
end
m.tok = lastTok
return res
endProcedure scanSpaceNL
/*--- skip over space, nl and comments and return m -----------------*/
scanSkip: procedure expose m.
parse arg m
call scanSpaceNl m
return m
endProcedure scanSkip
/* copy scan end ****************************************************/