zOs/REXX/COMP

/* copy comp begin ****************************************************
    the shell compiler
         syntax and semantics of the shell language see javaDoc
**********************************************************************/
/***** initialisation ************************************************/
/*--- module initialisation -----------------------------------------*/
compIni: procedure expose m.
    if m.compIni = 1 then
        return
    m.compIni = 1
    call pipeIni
    call scanReadIni
    cc = classNew('n Compiler u')
    call mNewArea 'COMP.AST', '='

    m.comp_chOp   = '.-<@|?%^'
    m.comp_chKind = '.-=#@:%^'
    m.comp_chKindDesc = 'Obj Str Skel Text Exe Wsh Call Fun'
    m.comp_chKiNO = '=:#'
    m.comp_chKiNBOE = '=<#:' /* nonBLock only expression not Primary*/
    m.comp_chDol = '$'
    m.comp_chSpa = m.ut_space
    call mPut 'COMP_EXTYPE.b', m.comp_chDol'{}'       /* braces */
    call mPut 'COMP_EXTYPE.d', m.comp_chDol            /* data */
    call mPut 'COMP_EXTYPE.s', m.comp_chDol            /* strip */
    call mPut 'COMP_EXTYPE.w', m.comp_chDol||m.comp_chSpa /* word */

    m.comp_idChars  = m.ut_alfNum'@_'
    m.comp_wCatC    = 'compile'
    m.comp_wCatS    = 'do withNew with for forWith ct proc arg if else'
    m.comp_astOps   = m.comp_chOp'])&'
    m.comp_astOut   = '.-@<^' /*ast kind for call out */
    m.comp_astStats = ''
    return
endProcedure compIni

compKindDesc: procedure expose m.
parse arg ki
    kx = pos(ki, m.comp_chKind)
    if length(ki) == 1 & kx > > 0 then
        return "kind"word(m.comp_chKindDesc, kx)"'"ki"'"
    else
        return "badKind'"ki"'"
endProcedure compKindDesc

/*--- constructor of Compiler ---------------------------------------*/
comp: procedure expose m.
parse arg src
    nn = oNew('Compiler')
    m.nn.cmpRdr = in2File(src)
    return nn
endProcedure comp

/*--- compile one unit of the source with kind ki
           and return oRunner with the code -------------------------*/
compile: procedure expose m.
parse arg m, ki, hook
    s = m.m.scan
    m.m.comp_assVars = 0
    call compSpComment m
    a = ''
    if m.m.end \== '' then
        call scanNlUntil s, '$#out'
    else if ki == '*' then
        call scanNlUntil s, '$#'
    else
        a = compUnit(m, ki, '$#')
    if compIsEmpty(m, a, 0) then
        return ''
    cd = compAst2Rx(m, ']', a)
    if 0 then
        say cd
    return oRunner(cd)
endProcedure compile

compBegin: procedure expose m.
parse arg m, spec
    m.m.scan = m'.scan'
    m.m.out = ''
    m.m.end = ''
    s = m.m.scan
    if m.m.cmpRdr == '' then
        call scanOpt scanSrc(s, spec), , '0123456789'
    else
        call scanReadOpen scanReadReset(scanOpt(s, , '0123456789'),
                          , m.m.cmpRdr), spec' '
    return m
endProcedure compBegin

compEnd: procedure expose m.
parse arg m, erKi
    s = m.m.scan
    if erKi \== '' then
        if \ scanEnd(s) then
            return scanErr(s, 'wsh' compKindDesc(erKi),
                   "expected: compile stopped before end of input")
    call scanClose s
    return m
endProcedure compEnd

/*--- parse the whole syntax of a unit ------------------------------*/
compUnit: procedure expose m.
parse arg m, ki, stopper
    s = m.m.scan
    if pos(ki, m.comp_chKind) < 1 then
        return scanErr(s, 'bad kind' ki 'in compUnit(...'stopper')')
    else if ki <> '#' then do
        a = compAst(m, '[')
        do forever
            one = compPipe(m, ki)
            if one \== '' then
                call mAdd a, one
            if \ scanLit(m.m.scan, '$;', '<>', '$<>') then
                return compUnNest(a)
            end
        end
    else do
        res = compAST(m, '[')
        call scanChar s
        if verify(m.s.tok, m.comp_chSpa) > 0 then
            call mAdd res, compAst(m, '=', strip(m.s.tok, 't'))
        do while scanNL(s, 1) & \ abbrev(m.s.src, stopper)
            call mAdd res, compAst(m, '=', strip(m.s.src, 't'))
            end
        return res
        end
endProcedure compUnit

compUnnest: procedure expose m.
parse arg a
    do while m.a.0 = 1 & pos(m.a.kind, '[-.;') > 0
        n = m.a.1
        if m.a.kind \== m.n.kind then
            return a
        call mFree a
        a = n
        end
    return a
endProcedure compUnnest

/*--- compile an expression, type d=data, b=block w=word, s=strip ---*/
compExpr: procedure expose m.
parse arg m, type, ki, textEnd
    s = m.m.scan
    if symbol('m.comp_exType.type') \== 'VAR' then
        call err s, 'bad type' type 'in compExpr'
    if ki == '#' then do
        if textEnd == '' then
            call scanChar(s)
        else if textEnd <= m.s.pos then
            return ''
        else
            call scanChar s, textEnd - m.s.pos
        if type == 's' then
            res = compAst(m, '=', strip(m.s.tok))
        else
            res = compAst(m, '=', , m.s.tok)
        res = compAST(m, '-', , res)
        m.res.containsC = 1
        m.res.containsD = 1
        return res
        end
    else if ki == '%' | ki == '^' then do
        call compSpComment m
        vr = compVar(m, left('c', ki == '^'))
        if vr == '' then
            return ''
        if m.vr.var == 'c' then
            res = compAst(m, 'M')
        else
            res = compAst(m, ki, , compASTAddOp(m, vr, '&'))
        call compSpComment m
        if textEnd == '' | textEnd < m.s.pos then do
            ex = compOpBE(m, '=', 1, , textEnd)
            if ex \== '' then do
                call mAdd res, ex
                call compSpComment m
                end
            end
        m.res.containsC = 1
        m.res.containsD = 1
        return res
        end

    if length(ki) \== 1 | pos(ki, '.-=@') < 1 then
        return scanErr(s, 'bad kind' ki 'in compExpr')
    res = compAST(m, translate(ki, '-;', '=@'))
    m.res.containsC = 0
    txtKi = translate(ki, '++=+', '.-=@')
    laPrim = 0
    gotTxt = 0
    if pos(type, 'sb') > 0 then
        m.res.containsC = compSpComment(m) >= 2
    do forever
        if textEnd \== '' then
            if m.s.pos >= textEnd then
                leave
        if scanVerify(s, m.comp_exType.type, 'm') then do
            if textEnd \== '' then
                if m.s.pos > textEnd then do
                    m.s.tok = left(m.s.tok, length(m.s.tok) ,
                                    + textEnd - m.s.pos)
                    m.s.pos = textEnd
                    end
            one = compAST(m, txtKi, m.s.tok)
            if verify(m.s.tok, m.comp_chSpa) > 0 then
                gotTxt = 1
            end
        else do
            old = scanPos(s)
            if \ scanLit(s, m.comp_chDol) then
                leave

            if pos(scanLook(s, 1), '.-') > 0 then
                one = compCheckNN(m, compOpBE(m, , 1, 0),
                   , 'primary block or expression expected')
            else
                one = compPrimary(m)
            if one = '' then do
                call scanBackPos s, old
                leave
                end
            laPrim = m.res.0 + 1
            end
        call mAdd res, one
        if compComment(m) then
            m.res.containsC = 1
        end
    if pos(type, 'bs') > 0 then do
        do rx=m.res.0 by -1 to laPrim+1
            one = m.res.rx
            m.one.text = strip(m.one.text, 't')
            if length(m.one.text) <> 0 then
                leave
            call mFree one
            end
        m.res.0 = rx
        end
    m.res.containsD = laPrim > 0 | gotTxt
    return compAstFree0(res, '')
endProcedure compExpr

/*--- compile a primary and return code -----------------------------*/
compPrimary: procedure expose m.
parse arg m, ops
    s = m.m.scan
    if scanString(s) then
        return compASTAddOp(m, compAST(m, '=', m.s.val), ops)
    r = compVar(m, left('c', right(ops, 1) == '^'))
    if r == '' then
        return ''
    if m.r.var \== 'c' then
         return compASTAddOp(m, compAst(m, '&', m.r.var, r), ops)
    else
         return compASTAddOp(m, compAst(m, 'M'),
                              , left(ops, length(ops)-1))
endProcedure compPrimary

/*--- oPBE ops (primary or block or expression)
       oDef = default Kind, oPre = opPrefix,
       uniq=1 extract unique, uniq='<' prefix <
       withEx <> 0: expression allowed ------------------------------*/
compOpBE: procedure expose m.
parse arg m, oDef, uniq, withEx, textEnd
    s = m.m.scan
    old = scanPos(s)
    op = compOpKind(m, oDef)
    if uniq == '<' & left(op, 1) \== '<' then
        op = left('<', uniq == '<') || op
    if pos(scanLook(s, 1), '/[') > 0 then do
        if uniq == 1 & length(op) == 1 then
            if op == '.' then
                op = '|.'
            else if op == '=' then
                op = '-='
            else if pos(op, '-@<') > 0 then
                op = op || op
        return compBlock(m, op)
        end
    if compSpComment(m) == 0 ,
        & pos(right(op, 1), m.comp_chKiNBOE) <= 0 then
        return compPrimary(m, op)
    if withEx \== 0 then do
        res = compExpr(m, 's', right(op, 1), textEnd)
        if res \== '' then
            return compASTAddOp(m, res, left(op, length(op)-1))
        end
    call scanBackPos s, old
    return ''
endProcedure compOPBE

/*--- compile var of ^or % clause -----------------------------------*/
compCallVar: procedure expose m.
parse arg m, ki
    call compSpComment m
    vr = compVar(m, left('c', ki == '^'))
    if vr == '' then
        call scanErr m.m.scan, 'var expected after' ki
    call compSpComment m
    if m.vr.var == 'c' then
        return compAst(m, 'M')
    else
        return compAst(m, ki, , compASTAddOp(m, vr, '&'))
endProcedure compCallVar

/*--- compile a pipe and return code --------------------------------*/
compPipe: procedure expose m.
parse arg m, ki
    s = m.m.scan
    res = compAST(m, 'P', ' ', '', '')
    do forever
        one = compExprStmts(m, ki)
        if one \== '' then do
            if m.res.0 > 2 then
                call scanErr s, '$| before statements needed'
            call mAdd res, one
            end
        pre = left(m.comp_chDol, scanLit(s, m.comp_chDol))
        if scanLook(s, 2) == '<>' then
            leave
        if scanLit(s, '<') then do
            if m.res.2 == '' then
                m.res.2 = compAst(m, '.')
            else
                call mAdd m.res.2, compAst(m, '+', ', ')
            call mAdd m.res.2, compOpBE(m, '<', '<')
            m.res.text = m.res.text'f'
            end
        else if scanLit(s, '>>', '>') then do
            if m.res.1 <> '' then
                call scanErr s, 'duplicate output'
            m.res.text = if(m.s.tok == '>', 'F', 'A') ,
                ||substr(m.res.text, 2)
            m.res.1 = compOpBE(m, '<', '<')
            end
        else if scanLit(s, '|') then do
            if m.res.0 < 3 then
                call scanErr s, 'stmts expected before |'
            call compSpNlComment m
            call mAdd res, compCheckNE(m, compExprStmts(m, ki),
                , 'stmts or expressions after | expected')
            end
        else
            leave
        end
    call scanBack s, pre
    if m.res.0 > 3 | m.res.1 \== '' | m.res.2 \== '' then
        return res
    one = if(m.res.0 = 3, m.res.3)
    call mFree res
    return one
endProcedure compPipe

/*--- compile expressions and stmts ---------------------------------*/
compExprStmts: procedure expose m.
parse arg m, ki
    s = m.m.scan
    res = compAst(m, '[')
    nlLe = 0 /* sophisticated logic using left and right NLs*/
    do forever
        one = compExprStm1(m, ki, nlLe)
        if one == '' then
            return compAstFree0(res)
        call mAdd res, one
        nlLe = scanNl(s)
        end
endProcedure compExprStmts

/*--- scan over space comm nl until next
          expression or statement and compile it --------------------*/
compExprStm1: procedure expose m.
parse arg m, ki, nlLe
    s = m.m.scan
    if pos(ki, ':%^') > 0 then do /* statements with $ are ok */
        call compSpNlComment m, '*'
        if ki \== ':' then do
            one = compExpr(m, 's', ki)
            if one \== '' then
                return one
            end
        end
    else if ki == '@' then do /* rexx statements */
        call compSpNlComment m
        one = compExpr(m, 's', ki)
        if one\ == '' then do
            if m.one.0 < 1 then
                call scanErr s, 'assert not empty' m.one.0
            do forever /* scan all continued rexx lines */
                la = m.one.0
                la = m.one.la
                if m.la.kind \== '+' then
                    leave
                m.la.text = strip(m.la.text, 't')
                if right(m.la.text, 1) \== ',' then
                    leave
                m.la.text = strip(left(m.la.text,
                        , length(m.la.text)-1), 't')' '
                call compSpNlComment m
                cont = compExpr(m, 's', '@')
                if cont == '' | m.cont.kind \== m.one.kind then
                    call scanErr s, 'bad rexx continuation'
                call mAddSt one, cont
                call mFree cont
                end
            return compAstFree0(one)
            end
        end
    else do /* statemens need $, nl logic for expr */
        do forever /* tricky logic for empty lines */
            do forever
                sx = m.s.pos
                call scanSpaceOnly s
                if \ compComment(m) then
                    leave
                nlLe = 0
                end
            m.s.pos = sx
            one = compExpr(m, 'd', ki)
            nlRi = scanNL(s, '?')
            if one == '' then do
                if nlLe & nlRi then
                    return compAst(m, translate(ki, ';-', '@=') ,
                                  , ,compAst(m,'='))
                end
            else if m.one.containsD then
                return one
            if \ nlRi then
                leave
            nlLe = scanNL(s)
            end
        end
    return compStmt(m, ki)
endProcedure compExprStm1

/*--- compile a single statement ------------------------------------*/
compStmt: procedure expose m.
parse arg m, ki
    s = m.m.scan
    res = compAss(m)
    if res \== '' then
        return res
    pre = ''
    old = scanPos(s)
    if scanLit(s,m.comp_chDol'$',m.comp_chDol'@',m.comp_chDol,'@') then
        pre = m.s.tok
    if pre == m.comp_chDol'$' then
        return  compCheckNN(m, compOpBE(m,'=', 1),
                   , 'block or expression expected after $$')
    if right(pre, 1) == '@' then do
        one = compOpBE(m, '@')
        if one \== '' then
            return compAstAddOp(m, one, ')')
        end

    wCat = compName(m, 'sv')
    fu = m.s.tok

    if right(pre, 1) == '@' & wCat \== 's' then
        call scanErr s, 'primary, block or expression expected'

    if fu == 'arg' then do
        res = compAst(m, 'R')
        do forever
            call compSpComment m
            if scanLit(s, ',') then
                a1 = compAst(m, '+', ',')
            else do
                gotV = 1
                a1 = compVar(m, 'v')
                end
            if a1 \== '' then
                call mAdd res, a1
            else if gotV == 1 then
                return res
            else
                call scanErr s, 'empty arg'
            end
        end

    if fu == 'ct' then do
        call compSpComment m
        return compAst(m, 'C', , compCheckNN(m, compExprStm1(m, ki, 0),
            , 'ct statement'))
        end

    if fu == 'do' then do
        call compSpComment m
        pre = compExpr(m, 's', '@')
        res = compAst(m, 'D', , pre)
        p1 = m.pre.1
        if pre \== '' then do
            txt = ''
            do px=1 to m.pre.0
                pC = m.pre.px
                if m.pC.kind \== '+' then
                    leave
                txt = txt m.pC.text
                cx = pos('=', txt)
                if cx > 0 then do
                    m.res.text = strip(left(txt, cx-1))
                    leave
                    end
                end
            end
        call compSpComment m
        call mAdd res, compCheckNN(m, compExprStm1(m, ki, 0),
                , 'stmt after do')
        return res
        end

    if wordPos(fu, 'for forWith with') > 0 then do
        res = compAst(m, 'F', fu)
        call compSpComment m
        if fu \== 'with' then do
            b = compVar(m)
            end
        else do
            b = compAss(m)
            if b == '' then
                b = compCheckNE(m, compExpr(m, 's', '.'),
                , "assignment or expression after with")
            end
        call compSpComment m
        st = compCheckNN(m, compExprStm1(m, ki, 0),
                        , "var? statement after" fu)
        if b = '' then do
            b = compBlockName(m, st)
            if b \== '' then
                b = compAst(m, '=', b)
            else if \ abbrev(fu, 'for') then
                call scanErr s, "variable or named block after" fu
            end
        call mAdd res, b, st
        return res
        end

    if fu == 'withNew' then do
        oldVars = m.m.comp_assVars
        m.m.comp_assVars = ''
        one = compCheckNN(m, compExprStm1(m, ki, 0), 'after withNew')
        r = compAst(m, 'F', 'withNew', '', one,
                          , compAst(m, '*', '].'))
        m.r.class = classNew('n* CompTable u' ,
                   substr(m.m.comp_assVars, 3))
        m.r.1 = compAst(m, '.', ,
                  , compAst(m, '+', "oNew('"m.r.class"')"))
        m.m.comp_assVars = oldVars
        return r
        end
    if fu == 'proc' then do
           call compSpComment m
        nm = ''
        if compName(m, 'v') == 'v' then do
            nm = m.s.tok
            call compSpComment m
            end
        st = compCheckNN(m, compExprStm1(m, ki, 0), 'proc statement')
        if nm == '' then do
            nm = compBlockName(m, st)
            if nm == '' then
                call scanErr s, 'var or namedBlock expected after proc'
            end
        return compAst(m, 'B', '', compAst(m, '=', nm), st)
        end
    if fu == 'if' | fu == 'else' then do /* unchanged rexx */
        call scanBack s, fu
        return compExpr(m, 's', '@')
        end
    call scanBack s, pre || fu
    return ''
endProcedure compStmt

compBlockName: procedure expose m.
parse arg m, a
    a1 = m.a.1
    if m.a.kind == '[' then
         return m.a.text
    else if m.a.kind == '*' & m.a1.kind == '[' then
        return m.a1.text
    return ''
endProcedure compBlockName

compVar: procedure expose m.
parse arg m, vk
    if pos('o', vk) > 0 then call err(sdf)/0
    s = m.m.scan
    ty = compName(m, 'v' || vk)
    if ty \== '' then do
        r = compAst(m, '=', m.s.tok)
        m.r.var = ty
        return r
        end
    if \ scanLit(s, '{') then
        return ''
    call scanLit s, '?', '>'
    f = m.s.tok
    r = compCheckNE(m, compExpr(m, 'b', '='), 'var name')
    if \scanLit(s, '}') then
        call scanErr s, 'closing } missing after {'
    m.r.var = f
    return r
endProcedure compVar

compAss: procedure expose m.
parse arg m, vk
    s = m.m.scan
    old = scanPos(s)
    call scanLit s, m.comp_chDol'=', '='
    pr = m.s.tok
    if pr \== '' then
        call compSpComment m
    v = compVar(m, vk)
    if v \== '' then do
        call compSpComment m
        if \ scanLit(s, '=') then do
            call scanBackPos s, old
            return ''
            end
        end
    else if pr == '' then
        return ''
    else
        oldInfo = scanInfo(s)
    eb = compCheckNE(m, compOpBE(m, '=', 1),
        , 'block or expression in assignment after' pr)
    if m.eb.kind == '[' then
        eb = compAstAddOp(m, eb, '-')
    if v == '' then do
        v = compBlockName(m, eb)
        if v == '' then
            call scanEr3 s, 'var or namedBlock expected',
                    'in assignment after' pr, oldInfo
        v = compAst(m, '=', v)
        m.v.var = 'v'
        end
    if m.m.comp_assVars \== 0 then
        if m.v.kind == '=' & m.v.var == 'v' then do
            if words(m.v.text) \= 1 then
                call compAstErr v, 'bad var'
            if m.eb.kind == '*' then
                ki = left(m.eb.text, 1)
            else
                ki = m.eb.kind
            if pos(ki, '-=s') > 0 then
                f = ', f' m.v.text 'v'
            else if pos(ki, '.<@o') > 0 then
                f = ', f' m.v.text 'r'
            else
                call compAstErr eb, 'string or object'
            if pos(f, m.m.comp_assVars) < 1 then
                m.m.comp_assVars = m.m.comp_assVars || f
            end
    return compAst(m, 'A', , v, eb)
endProcedure compAss

/*--- block deals with the correct kind and operators
      the content is parsed by compUnit -----------------------------*/
compBlock: procedure expose m.
parse arg m, ops
    s = m.m.scan
    if \ scanLit(s, '[', '/') then
        return ''
    start = m.s.tok
    if ops == '' | pos(right(ops, 1), m.comp_chKind) < 1 then
        return scanErr(s, 'bad kind' ops 'for block')
    ki = right(ops, 1)
    ops = left(ops, length(ops)-1)
    starter = start
    if start == '[' then
        stopper = m.comp_chDol']'
    else do
        call scanVerify s, '/', 'm'
        starter = '/'m.s.tok'/'
        stopper = m.comp_chDol || starter
        if \scanLit(s, '/') then
            call scanErr s, 'ending / after stopper' stopper 'expected'
        end
    res = compUnit(m, ki, stopper)
    if \ scanLit(s, stopper, substr(stopper, 2)) then
           call scanErr s, 'ending' stopper 'expected after' starter
    if abbrev(starter, '/') then
        m.res.text = substr(starter, 2, length(starter)-2)
    return compAstAddOp(m, res, ops)
endProcedure compBlock

/**** lexicals *******************************************************/
/*--- skip a comment. return 0 if there is none ---------------------*/
compComment: procedure expose m.
parse arg m
    s = m.m.scan
    got = 0
    do forever
        if scanLit(s, m.comp_chDol'**') then
            m.s.pos = 1 + length(m.s.src) /* before next nl */
        else if scanLit(s, m.comp_chDol'*+') then
            call scanNL s, 1
        else if scanLit(s, m.comp_chDol'*(') then do
            do forever
                if scanVerify(s, m.comp_chDol, 'm') then iterate
                if scanNL(s) then iterate
                if compComment(m) then iterate
                if \ scanLit(s, m.comp_chDol) then
                    call scanErr s, 'source end in comment'
                if scanLit(s, '*)') then
                    return 1
                if scanLit(s, m.comp_chDol) then iterate
                if scanString(s) then iterate
                end
            end
        else
            return got
        got = 1
        end
endProcedure compComment

/*--- skip spaces and comments --------------------------------------*/
compSpComment: procedure expose m.
parse arg m, xtra
    s = m.m.scan
    got = 0
    do forever
        if scanVerify(s, m.comp_chSpa) then
            got = bitOr(got, 1)
        else if compComment(m) then
            got = bitOr(got, 2)
        else if xtra == '' then
            return got
        else if \ scanLit(s, xtra) then
            return got
        else do
            got = bitOr(got, 4)
            m.s.pos = 1+length(m.s.src)
            end
        end
endProcedure compSpComment

/*--- skip spaces, NLs and comments ---------------------------------*/
compSpNlComment: procedure expose m.
parse arg m, xtra
    found = 0
    do forever
        if compSpComment(m, xtra) < 1 then
            if \ scanNL(m.m.scan) then
             return found
        found = 1
        end
endProcedure compSpNlComment
/*--- scan a name in one of the categories
        v=var, c=compile, s=stmt ----------------------------------*/
compName: procedure expose m.
parse arg m, cats
    s = m.m.scan
    if \ scanName(s) then
        return ''
    if wordPos(m.s.tok, m.comp_wCatS) > 0 then do
        if pos('s', cats) > 0 then
            return 's'
        end
    else if wordPos(m.s.tok, m.comp_wCatC) > 0 then do
        if pos('c', cats) > 0 then
            return 'c'
        end
    else if pos('v', cats) > 0 then do
        return 'v'
        end
    call scanBack s, m.s.tok
    return ''
endProcedure compName

compOpKind: procedure expose m.
parse arg m, op
    s = m.m.scan
    if scanVerify(s, m.comp_chOp || m.comp_chKiNO) then
        op = m.s.tok
    else if op == '' then
        return ''
    /* ??????? temporary until old syntax vanished ????? */
    x = verify(op, '%^', 'm')
    if x > 0 & x < length(op) then
        call scanErr s, 'old syntax? run not at end'
    if right(op, 1) == '<' then
        op = op'='
    kx = verify(op, m.comp_chKiNO, 'm')
    if kx \== 0 & kx \== length(op) then
        call scanErr s, 'kind' substr(op, kx, 1) 'not after ops'
    if pos(right(op, 1), m.comp_chKind) == 0 then
        call scanErr s, 'no kind after ops' op
    return op
endProcedure compOpKind

compSpNlComment: procedure expose m.
/**** small helper routines ******************************************/
/*--- if va == null then issue an error with msg --------------------*/
compCheckNN: procedure expose m.
parse arg m, va, msg
    if va == '' then
        call scanErr m.m.scan, msg 'expected'
    return va
endProcedure compCheckNN

/*--- return true iff expression is empty ---------------------------*/
compIsEmpty: procedure expose m.
parse arg m, a, block0
    do forever
        if a == '' then
            return 1
        else if m.a.kind == '*' then
            a = m.a.1
        else if m.a.kind \== '[' then
            return 0
        else if block0 then
            return 0
        else if m.a.0 = 1 then
            a = m.a.1
        else
            return m.a.0 < 1
        end
endProcedure compIsEmpty

/*--- if va == null or empty then issue an error with msg -----------*/
compCheckNE: procedure expose m.
parse arg m, ex, msg
    e1 = left(ex, 1)
    if compIsEmpty(m, ex, 1) then
        call scanErr m.m.scan, msg 'expected'
    return ex
endProcedure compCheckNE

/**** AST = Astract Syntax Tree ***************************************

------- atoms, no children
  =  string constant
  +  rexx fragment

------- containers (any number of children)
  -  string expression
  .  object expression
  ;  rexx statements
  [  block

------- molecules
  *  operand chain  ==> 1 operands in text, as in syntax plus
                          ) run ($@ stmt), & variable access, ] execute
  &  variable access==> 1
  A  assignment     ==> 2
  B  proc           ==> 2
  C  ct             ==> 1
  D  do             ==> 2
  F  for + with     ==> 2
  P  Pipe           ==> * 1=input 2=output , 3..* piped stmtBlocks
  R  aRg                * list of arguments/separators
  T  Table
  M  compile
  %  RunOut         ==> 1,2 (Run, arguments)
  ^  RunRet         ==> 1,2 (Run, arguments)

**********************************************************************/
/*--- create a new AST ----------------------------------------------*/
compAST: procedure expose m.
parse arg m, ki, txt
    n = mNew('COMP.AST')
    if length(ki) <> 1 then
        return err('compAST bad kind' ki) / 0
    m.n.kind = ki
    m.n.text = txt
    if pos(ki, '[;-.*&ABCDFPRTM%^') > 0 then do
        do cx=1 to arg()-3
            m.n.cx = arg(cx+3)
            end
        m.n.0 = cx-1
        if ki == '*' then do
            if verify(txt, m.comp_astOps) > 0 then
                return err('compAst ki=* bad ops:' txt) / 0
            end
        else if txt \== '' & pos(ki, '&*FPT') < 1 then
            return err('kind' ki 'text='txt'|')/0
        end
    else if pos(ki, '=+') > 0  then do
        m.n.0 = 'kind'ki
        end
    else do
        return err( "compAst kind '"ki"' not supported") / 0
        end
    return n
endProcedure compAST

/*--- free AST if empty ---------------------------------------------*/
compASTFree0: procedure expose m.
parse arg a, ret
    if m.a.0 > 0 then
        return a
    call mFree a
    return ret
endProcedure compAstFree0

/*--- add operandands to an AST -------------------------------------*/
compASTAddOp: procedure expose m.
parse arg m, a, ops
    if verify(ops, m.comp_astOps) > 0 then
        return err('addOp bad ops:' ops) / 0
    k = if(m.a.kind=='*', left(m.a.text, 1), m.a.kind)
    do while right(ops, 1) == k
        ops = left(ops, length(ops)-1)
        end
    if ops == '' then
        return a
    if ki \== '*' then
        return compAst(m, '*', ops, a)
    m.a.text = ops || m.a.text
    return a
endProcedure compAstAddOp

/*--- return the kind of an AST -------------------------------------*/
compASTKind: procedure expose m.
parse arg m, a
    m.m.astOps = ''
    if \ abbrev(a, 'COMP.AST.') then
        return left(a, 1)
    c = a
    do while m.c.kind == 'ops'
        if m.c.text \== '' then
            return left(m.c.text, 1)
        c = m.c.1
        end
    if a == c then
        return '?'
    return compAstKind(m, c)
endProcedure compASTKind

compAstSay: procedure expose m.
parse arg a, lv
    if \ abbrev(a, 'COMP.AST.') then do
        if a \== '' then
            return err('bad ast' a)
        say left('', 19)': * empty ast'
        return
        end
    say lefPad(left('', lv) m.a.kind, 10) ,
        || rigPad(if(dataType(m.a.0, 'n'), m.a.0), 3),
        '@'rigPad(substr(a, 10), 4)':' m.a.text'|'
    if dataType(m.a.0, 'n') then do cx=1 to m.a.0
        call compAstSay m.a.cx, lv+1
        end
    return
endProcedure compAstSay

compAstErr: procedure expose m.
parse arg a, txt
    call errSay txt
    call compAstSay a, 0
    return err(txt)
endProcedure compAstErr

/*--- return the code for an AST with operand chain trg -------------*/
compCode2rx: procedure expose m.
parse arg m, ops, f
    if ops == '' then
        return f
    o1 = right(ops, 1)
    oR = left(ops, length(ops)-1)
    if pos(o1, ')]') > 0 then
        return compCode2rx(m, oR, strip(f))
    if pos(o1, '-.<|?@') > 0 then
        return compRun2rx(m, ops, quote(oRunner(f)))
    call err 'compCode2rx bad ops' ops 'code='f
endProcedure compCode2rx

compCon2rx: procedure expose m.
parse arg m, ops, f, a
    do ox=length(ops) by -1 to 1 while pos(substr(ops,ox,1), '.-')>0
        end
    if substr(ops, ox+1, 1) == '.' then
        f = s2o(f)
    if length(f) < 20 then
        v = quote(f, "'")
    else if a \== '' & m.a.text == f then
        v = 'm.'a'.text'
    else
        v = 'm.'compAst(m, '=', f)'.text'
    if substr(ops, ox+1, 1) == '.' then
        return compObj2rx(m, left(ops, ox), v)
    else
        return compString2rx(m, left(ops, ox), v)
endProcedure compCon2rx

compString2rx: procedure expose m.
parse arg m, ops, f
    if ops == '' then
        return f
    o1 = right(ops, 1)
    oR = left(ops, length(ops)-1)
    if pos(o1, ']') then
        return compCode2rx(m, oR, 'call out' f)
    if o1 == '-' then
        return compString2rx(m, oR, f)
    if o1 == '.' then
        return compObj2rx(m, oR, 's2o('f')')
    if o1 == '&' then do
        o2 = substr('1'ops, length(ops), 1)
        if pos(o2,  '.<^%@)') < 1 then
            return compString2rx(m, oR, 'vGet('f')')
        else
            return compObj2rx(m, oR, 'vGet('f')')
        end
    if o1 == '<' then
        return compFile2rx(m, oR, 'file('f')')
    call err 'compString2rx bad ops' ops
endProcedure compString2rx

compObj2rx: procedure expose m.
parse arg m, ops, f
    if ops == '' then
        return f
    o1 = right(ops, 1)
    oR = left(ops, length(ops)-1)
    if o1 == '.' then
        return compObj2rx(m, oR, f)
    if o1 == '-' then
        return compString2rx(m, oR, 'o2string('f')')
    if o1 == ']' then
        return compCode2rx(m, oR, 'call out' f)
    if o1 == '<' then
        return compFile2rx(m, oR, 'o2file('f')')
    if o1 == '@' then
        return compRun2Rx(m, oR, f)
    if pos(o1, ')%^') > 0 then
        return compRun2rx(m, ops, f)
    call err 'compObj2rx bad ops' ops 'for' f
endProcedure compObj2rx

compRun2rx: procedure expose m.
parse arg m, ops, f
    if ops == '' then
        return f
    o1 = right(ops, 1)
    oR = left(ops, length(ops)-1)
    if o1 == '@' then
        return compRun2Rx(m, oR, f)
    if pos(o1, ')%') > 0 then
        return compCode2Rx(m, oR, 'call oRun' f)
    if o1 == '^' then
        if pos(right(oR, 1),  '.<^%') < 1 then
            return compString2Rx(m, oR, 'oRun('f')')
        else
            return compObj2Rx(m, oR, 'oRun('f')')
    return compObj2rx(m, ops, f)
endProcedure compRun2rx

compFile2rx: procedure expose m.
parse arg m, ops, f
    if ops == '' then
        return f
    o1 = right(ops, 1)
    oR = left(ops, length(ops)-1)
    if pos(o1, '<.@') > 0 then
        return compFile2rx(m, oR, f)
    if o1 == '|' | o1 == '?' then
        return compObj2Rx(m, oR, 'jSingle('f ||if(o1=='?', ", ''")')')
    return compRun2rx(m, ops, f)
endProcedure compFile2rx

compAst2rx: procedure expose m.
parse arg m, ops, a
    ki = m.a.kind
    /* astStats ausgeschaltet
    if pos(ki, m.comp_astStats) < 1 then do
        m.comp_astStats = m.comp_astStats ki
        m.comp_astStats.ki = 0
        m.comp_astStatT.ki = 0
        end
    m.comp_astStats.ki = m.comp_astStats.ki + 1
    if m.a.text \== '' then
        m.comp_astStatT.ki = m.comp_astStatT.ki + 1
    if ki == '*' then do
        k2 = vGet(a'.1>>KIND')
        if symbol('m.comp_astStat1.k2') \== 'VAR' then
            m.comp_astStat1.k2 = 1
        else
            m.comp_astStat1.k2 = m.comp_astStat1.k2 + 1
        end         */
    if ki == '+' & ops == '' then
        return m.a.text
    if ki == '=' then
        return compCon2Rx(m, ops, m.a.text, a)
    if ki == '*' then
        return compAst2Rx(m, ops || m.a.text, m.a.1)
    o1 = right(ops, 1)
    oR = left(ops, max(0, length(ops)-1))
    if ki == '-' then
        return compString2rx(m, ops, compCatRexxAll(m, a,,, ' || '))
    if ki == '.' then
        return compObj2Rx(m, ops, compCatRexxAll(m, a,,, ' || '))
    if ki == ';' then
        return compCode2Rx(m, ops, compCatRexxAll(m, a,,,' || '))
    if ki == '[' then do
        a1 = m.a.1
        if m.a.0 == 1 & m.a1.kind == '[' then
            return compAst2Rx(m, ops, a1)
        if o1 == '-' then do
            res = compAst2CatStr(m, a)
            if res \== '' then /* () necessary if part of expression */
                return compString2rx(m, oR, '('strip(res)')')
            end
        if o1 == '.' then
            return compAst2Rx(m, ops'|', a)
        if pos(o1, '|?') > 0 then
            if m.a.0 = 1 & compAstOut(a1) then
                return compAst2Rx(m, oR, a1)
        res = ''
        do ax=1 to m.a.0
            res = res';' compAst2rx(m, ']', m.a.ax)
            end
        if verify(res, '; ') = 0 then
            res = 'nop'
        else
            res = 'do'res'; end'
        if pos(o1, '-@])') > 0 then
            return compCode2Rx(m, ops, res)
        if pos(o1, '|?<') > 0 then
            return compCode2Rx(m, ops'<@', res)
        end
    if ki == '&' then do
        nm = compAst2Rx(m, '-', m.a.1)
        if m.a.text=='' | m.a.text=='v' then
            return compString2rx(m, ops'&', nm)
        else if m.a.text == '?' then
            return compString2rx(m, ops, 'vIsDefined('nm')')
        else if m.a.text == '>' then
            return compString2rx(m, ops, 'vIn('nm')')
        else
            call compAstErr a, 'bad text' m.a.text 'in ast &'
        end
    if ki == '%' | ki == '^' then do
        c1 = compAst2Rx(m, '.', m.a.1)
        if m.a.0 > 1 then
            c1 =  c1',' compAst2Rx(m, '', m.a.2)
        return compRun2Rx(m, ops || ki, c1)
        end
    if ki == 'A' then do /* assignment */
        nm = compAst2Rx(m, '-', m.a.1)
        vl = m.a.2
        if m.vl.kind == '=' | m.vl.kind == '-' ,
            | (m.vl.kind == '*' & right(m.vl.text, 1) == '-') then
            return compCode2Rx(m, ops,
                , 'call vPut' nm',' compAst2Rx(m, '-', vl))
        else
            return compCode2Rx(m, ops,
                , 'call vPut' nm',' compAst2Rx(m, '.', vl))
        end
    if ki == 'B' then do /* proc */
        call vPut utInter('return' compAst2Rx(m, '-', m.a.1)),
            , oRunner(compAst2Rx(m ,']', m.a.2))
        return ''
        end
    if ki == 'C' then do /* ct */
     call utInter compAst2Rx(m, ']', m.a.1)
        return ''
        end
    if ki == 'D' then do /* do */
        res = 'do' compAst2rx(m, '', m.a.1)
        if m.a.text \== '' then
            res = res"; call vPut '"m.a.text"'," m.a.text
        return compCode2Rx(m, ops, res';' compAst2Rx(m, ']', m.a.2),
             || "; end")
        end
    if ki == 'F' then do /* for... */
        a1 = m.a.1
        st = compAst2Rx(m, ']', m.a.2)
        if abbrev(m.a.text, 'for') then do
            if m.a.1 == '' then
                v = "''"
            else
                v = compAst2Rx(m, '-', m.a.1)
            if m.a.text == 'for' then
                s1 = 'do while vIn('v')'
            else if m.a.text \== 'forWith' then
                call compAstErr a, 'bad for...'
            else
                s1 = 'call vWith "+"; do while vForWith('v')'
            return compCode2Rx(m, ops, s1';' st'; end')
            end
        else if \ abbrev(m.a.text, 'with') then
            call compAstErr a, 'bad with...'
        if m.a1.kind \== 'A' then do
            v = compAst2Rx(m, '.', a1)
            end
         else do
            v = compAst2Rx(m, ,a1)
            if \ abbrev(v, 'call vPut ') | pos(';', v) > 0 then
                call scanErr s, 'bad vPut' v
            v = 'vPut('substr(v, 11)')'
            end
        ret1 = 'call vWith "+",' v';' st
        if m.a.0 <= 2 then
            return ret1"; call vWith '-'"
        a3 = m.a.3
        if m.a3.kind \== '*' then
            call compAstErr a, 'for/with a.3 not *'
        return ret1';' compObj2Rx(m, m.a3.text, "vWith('-')")
        end
    if ki == 'P' then do /* pipe */
        if ((left(m.a.text, 1) == ' ') \== (m.a.1 == '')) ,
         | ((substr(m.a.text, 2) == '') \== (m.a.2 == '')) ,
         | (m.a.0 <= 3 & m.a.text == '') then
            call compAstErr a, 'bad/trivial astPipe'
        res = ''
        do ax=3 to m.a.0
            a1 = ''
            if ax < m.a.0 then /* handle output */
                t1 = 'N'
            else if m.a.1 == '' then
                t1 = 'P'
            else do
                t1 = left(m.a.text, 1)
                a1 = compAst2Rx(m, '.', m.a.1)
                end
            if ax == 3 then do /* handle input */
                t1 = '+'t1 || substr(m.a.text, 2)
                if m.a.2 \== '' then
                    a1 = a1',' compAst2Rx(m, '.', m.a.2)
                end
            else
                t1 = t1'|'
            res = res"; call pipe '"t1"'," a1 ,
                   ";" compAst2Rx(m, ']', m.a.ax)
            end
        return compCode2Rx(m, ops, substr(res, 3)"; call pipe '-'")
        end
    if ki == 'R' then do /* aRg statement */
        prs = 'parse arg ,'
        pts = ''
        do ax=1 to m.a.0
            a1 = m.a.ax
            if m.a1.kind = '+' & m.a1.text == ',' then
                prs = prs','
            else do
                prs = prs 'ggAA'ax
                pts = pts'; call vPut' compAst2Rx(m, '-', a1)', ggAA'ax
                end
            end
        return compCode2rx(m, ops, prs pts)
        end
    if ki == 'M' then do
        if m.a.0 = 0 then
            args = ''
        else
            args = compAst2Rx(m, , m.a.1)
        return compRun2rx(m, ops, 'wshHookComp( ,'args ',in2Buf())')
        end
    return compAstErr(a, 'compAst2rx bad ops='ops 'kind='ki 'ast='a)
endProcedure compAst2rx

compAstOut: procedure expose m.
parse arg a
    if m.a.kind \== '*' then
        return pos(m.a.kind, m.comp_astOut) > 0
    return pos(left(m.a.text, 1), m.comp_astOut) > 0
endProcedure compAstOut

compAst2CatStr: procedure expose m.
parse arg m, a
    res = ''
    if compAstOut(a) then
        res = compCatRexx(res, compAst2rx(m, , a), ' ')
    else if m.a.kind \== '[' then
        return ''
    else do ax=1 to m.a.0
        b = compAst2CatStr(m, m.a.ax)
        if b == '' then
            return ''
        res = compCatRexx(res, b, ' ')
        end
    return res
endProcedure compAst2CatStr

compCatRexxAll: procedure expose m.
parse arg m, a, ops, mi, sep
    res = ''
    do ax=1 to m.a.0
        a1 = m.a.ax
        res = compCatRexx(res, compAst2rx(m, ops, m.a.ax), mi , sep)
        end
    return strip(res)
endProcedure compCatRexxAll

/*--- cat two rexx parts, avoid strange effects ---------------------*/
compCatRexx: procedure expose m.
parse arg le, ri, mi, sep
    if mi \== '' then
        return le || mi || ri
    lr = right(le, 1)
    rl = left(ri, 1)
    if (lr == "'" | lr == '"') then do
        if rl == lr then                          /* "a","b" -> "ab" */
            return left(le, length(le)-1) || substr(ri, 2)
        else if  rl == '(' then                 /* "a",( -> "a" || ( */
            return le||sep||ri             /* avoid function call    */
        end
    else if pos(lr, m.comp_idChars) > 0 then
        if pos(rl, m.comp_idChars'(') > 0 then
            return le || sep || ri        /* a,b -> a || b */
    return le || ri
endProcedure compCatRexx
/* copy comp end *****************************************************/