segfault on parsing some inputs

SuperDoxin commented 8 years ago

given this grammar:

assemblyFile:
    list <- line+ EOF
    line <- :WS? (comment / instruction)
    comment <- :';' ~((!'\n' .)*) EOL / EOL
    label_list <- (label :WS?)*
    label <- ~(!opcode ([a-zA-Z_] [a-zA-Z0-9_]*))
    operation <- opcode :'.' modifier / opcode
    opcode <~ 'dat' / 'mov' / 'add' /
              'sub' / 'mul' / 'div' /
              'mod' / 'jmp' / 'jmz' /
              'jmn' / 'djn' / 'cmp' /
              'slt' / 'spl' / 'sne' /
              'seq' / 'org' / 'equ' / 
              'end'
    modifier <- 'ab' / 'ba' / 'a' / 'b' / 'f' / 'x' / 'i' / eps
    mode <- '#' / '$' / '@' / '<' / '>' / '{' / '}' / '*' / eps
    expr <- '(' expr ')' tail / term tail
    tail <- '%' expr / '/' expr / '*' expr / '-' expr / '+' expr / eps
    term <- label / number / expr
    number <- whole_number / signed_integer
    signed_integer <~ '+' whole_number / '-' whole_number
    whole_number <~ [0-9]+
    WS <- ' '+
    EOL <- :'\n' / EOF
    EOF <- !.

    instruction <- label_list :WS? operation :WS? mode :WS? expr :WS? ',' :WS? mode :WS? expr :WS? comment / 
                   label_list :WS? operation :WS? mode :WS? expr :WS? comment

and this input:

;redcode-94
;name Behemot
;author Michal Janeczek
;strategy MiniQ^3 -> Stun bomber
;assert CORESIZE==8000

       org   qGo

bStep  equ   2223
bDrop  equ   382

bDist  equ   3250
bcOff  equ   51
bgOff  equ   17

bRun   equ   (bHit-bInc*bDrop)
bGate  equ   (bClr-bgOff)
bSpl   equ   (bHit-2*bInc)+1
bJmp   equ   (bHit-2*bInc)-1
bInc   equ   3*bStep

bStart mov.i {0             , #0
bLoop  mov   bSpl           , <bPtr
       mov   bJmp           , *bPtr
bPtr   mov   bRun-bStep     , @bRun+bStep+1
bHit   add   *bEvac         , bPtr
       mov   >bJmp          , @bPtr
       jmz.a bLoop          , <bJmp
bEvac  jmp   -bcOff         , <1-bcOff-bgOff

bGo    spl   1              , bWipe+5
bcDst  spl   1              , bDist+4+bEvac-bcOff
       mov   <bGo           , <bbDst
       mov   <bGo           , <bcDst
       mov   <bBoot         , {bBoot
       mov   <bBoot         , {bBoot
bbDst  mov.i bGo            , #bDist+2+bSpl
bBoot  jmp   >bDist+bEvac+1 , bEvac+1

       spl   #bInc          , <bInc+1
bClr   mov   bWipe          , >bGate
       djn.f bClr           , >bGate
bWipe  dat   <2667          , 2-bGate

       jmp   bStep          , {1
       mov   @0             , }-1
       spl   #2             , -bStep

       for   35
       dat   0              , 0
       rof

qf     equ   qKil
qs     equ   222
qd     equ   322
qi     equ   7
qr     equ   11

qGo    seq   qd+qf+qs       , qf+qs
       jmp   qSki           , {qd+qf+qs+qi
       seq   qd+qf+6*qs     , qf+6*qs
       jmp   qFas           , {qd+qf+6*qs+qi
       seq   qd+qf+5*qs     , qf+5*qs
       jmp   qFas           , <qBmb
       seq   qd+qf+7*qs     , qf+7*qs
       jmp   qFas           , >qBmb
       seq   qd+qf+9*qs     , qf+9*qs
       djn   qFas           , {qFas
       seq   qd+qf+10*qs    , qf+10*qs
       jmp   qFas           , {qFas
       seq   qd+qf+3*qs     , qf+3*qs
       jmp   >qFas          , {qd+qf+3*qs+qi
       seq   qd+qf+2*qs     , qf+2*qs
       jmp   >qFas          , {qSlo
       seq   qd+qf+4*qs     , qf+4*qs
       jmp   >qFas          , }qSlo
       seq   qd+qf+12*qs    , qf+12*qs
       jmp   qSlo           , {qSlo
       seq   qd+qf+15*qs    , qf+15*qs
       jmp   qSlo           , <qBmb
       seq   qd+qf+21*qs    , qf+21*qs
       jmp   qSlo           , >qBmb
       seq   qd+qf+24*qs    , qf+24*qs
       jmp   qSlo           , }qSlo
       seq   qd+qf+27*qs    , qf+27*qs
       djn   qSlo           , {qFas
       seq   qd+qf+30*qs    , qf+30*qs
       jmp   qSlo           , {qFas
       sne   qd+qf+18*qs    , qf+18*qs
       jmz.f bGo            , qd+qf+18*qs-10
qSlo   mul.ab #3            , qKil
qFas   mul.b qBmb           , @qSlo
qSki   sne   >3456          , @qKil
       add   #qd            , qKil
qLoo   mov   qBmb           , @qKil
qKil   mov   qBmb           , *qs
       sub   #qi            , qKil
       djn   qLoo           , #qr
       jmp   bGo            , >10
qBmb   dat   {qi*qr-10      , {6

       end

I get a segfault. using gdb to inspect the stack trace doesn't do me good since the trace is thousands of frames deep, and I'm having massive trouble reading the pegged source to figure out what is going on.

I suspect the problem lies in expr and it's related rules, but I can't be sure. is there any better way to debug this?

do note that simpler inputs don't segfault.

veelo commented 8 years ago

Given issue_182.d with contents

import pegged.grammar;

mixin(grammar(`
    assemblyFile:
        list <- line+ EOF
        line <- :WS? (comment / instruction)
        comment <- :';' ~((!'\n' .)*) EOL / EOL
        label_list <- (label :WS?)*
        label <- ~(!opcode ([a-zA-Z_] [a-zA-Z0-9_]*))
        operation <- opcode :'.' modifier / opcode
        opcode <~ 'dat' / 'mov' / 'add' /
                  'sub' / 'mul' / 'div' /
                  'mod' / 'jmp' / 'jmz' /
                  'jmn' / 'djn' / 'cmp' /
                  'slt' / 'spl' / 'sne' /
                  'seq' / 'org' / 'equ' /
                  'end'
        modifier <- 'ab' / 'ba' / 'a' / 'b' / 'f' / 'x' / 'i' / eps
        mode <- '#' / '$' / '@' / '<' / '>' / '{' / '}' / '*' / eps
        expr <- '(' expr ')' tail / term tail
        tail <- '%' expr / '/' expr / '*' expr / '-' expr / '+' expr / eps
        term <- label / number / expr
        number <- whole_number / signed_integer
        signed_integer <~ '+' whole_number / '-' whole_number
        whole_number <~ [0-9]+
        WS <- ' '+
        EOL <- :'\n' / EOF
        EOF <- !.

        instruction <- label_list :WS? operation :WS? mode :WS? expr :WS? ',' :WS? mode :WS? expr :WS? comment /
                       label_list :WS? operation :WS? mode :WS? expr :WS? comment
`));

unittest
{
    enum input = `
    ;redcode-94
    ;name Behemot
    ;author Michal Janeczek
    ;strategy MiniQ^3 -> Stun bomber
    ;assert CORESIZE==8000

           org   qGo

    bStep  equ   2223
    bDrop  equ   382

    bDist  equ   3250
    bcOff  equ   51
    bgOff  equ   17

    bRun   equ   (bHit-bInc*bDrop)
    bGate  equ   (bClr-bgOff)
    bSpl   equ   (bHit-2*bInc)+1
    bJmp   equ   (bHit-2*bInc)-1
    bInc   equ   3*bStep

    bStart mov.i {0             , #0
    bLoop  mov   bSpl           , <bPtr
           mov   bJmp           , *bPtr
    bPtr   mov   bRun-bStep     , @bRun+bStep+1
    bHit   add   *bEvac         , bPtr
           mov   >bJmp          , @bPtr
           jmz.a bLoop          , <bJmp
    bEvac  jmp   -bcOff         , <1-bcOff-bgOff

    bGo    spl   1              , bWipe+5
    bcDst  spl   1              , bDist+4+bEvac-bcOff
           mov   <bGo           , <bbDst
           mov   <bGo           , <bcDst
           mov   <bBoot         , {bBoot
           mov   <bBoot         , {bBoot
    bbDst  mov.i bGo            , #bDist+2+bSpl
    bBoot  jmp   >bDist+bEvac+1 , bEvac+1

           spl   #bInc          , <bInc+1
    bClr   mov   bWipe          , >bGate
           djn.f bClr           , >bGate
    bWipe  dat   <2667          , 2-bGate

           jmp   bStep          , {1
           mov   @0             , }-1
           spl   #2             , -bStep

           for   35
           dat   0              , 0
           rof

    qf     equ   qKil
    qs     equ   222
    qd     equ   322
    qi     equ   7
    qr     equ   11

    qGo    seq   qd+qf+qs       , qf+qs
           jmp   qSki           , {qd+qf+qs+qi
           seq   qd+qf+6*qs     , qf+6*qs
           jmp   qFas           , {qd+qf+6*qs+qi
           seq   qd+qf+5*qs     , qf+5*qs
           jmp   qFas           , <qBmb
           seq   qd+qf+7*qs     , qf+7*qs
           jmp   qFas           , >qBmb
           seq   qd+qf+9*qs     , qf+9*qs
           djn   qFas           , {qFas
           seq   qd+qf+10*qs    , qf+10*qs
           jmp   qFas           , {qFas
           seq   qd+qf+3*qs     , qf+3*qs
           jmp   >qFas          , {qd+qf+3*qs+qi
           seq   qd+qf+2*qs     , qf+2*qs
           jmp   >qFas          , {qSlo
           seq   qd+qf+4*qs     , qf+4*qs
           jmp   >qFas          , }qSlo
           seq   qd+qf+12*qs    , qf+12*qs
           jmp   qSlo           , {qSlo
           seq   qd+qf+15*qs    , qf+15*qs
           jmp   qSlo           , <qBmb
           seq   qd+qf+21*qs    , qf+21*qs
           jmp   qSlo           , >qBmb
           seq   qd+qf+24*qs    , qf+24*qs
           jmp   qSlo           , }qSlo
           seq   qd+qf+27*qs    , qf+27*qs
           djn   qSlo           , {qFas
           seq   qd+qf+30*qs    , qf+30*qs
           jmp   qSlo           , {qFas
           sne   qd+qf+18*qs    , qf+18*qs
           jmz.f bGo            , qd+qf+18*qs-10
    qSlo   mul.ab #3            , qKil
    qFas   mul.b qBmb           , @qSlo
    qSki   sne   >3456          , @qKil
           add   #qd            , qKil
    qLoo   mov   qBmb           , @qKil
    qKil   mov   qBmb           , *qs
           sub   #qi            , qKil
           djn   qLoo           , #qr
           jmp   bGo            , >10
    qBmb   dat   {qi*qr-10      , {6

           end

`;
    import std.stdio;
    writeln(assemblyFile(input));
}

and testing with

rdmd -unittest -main -I"<Pegged-dir>" issue_182.d

I get this output:

assemblyFile (failure)
 +-assemblyFile.list (failure)
    +-assemblyFile.line [1, 17]["redcode-94"]
    |  +-assemblyFile.comment [5, 17]["redcode-94"]
    +-assemblyFile.line [17, 35]["name Behemot"]
    |  +-assemblyFile.comment [21, 35]["name Behemot"]
    +-assemblyFile.line [35, 63]["author Michal Janeczek"]
    |  +-assemblyFile.comment [39, 63]["author Michal Janeczek"]
    +-assemblyFile.line [63, 100]["strategy MiniQ^3 -> Stun bomber"]
    |  +-assemblyFile.comment [67, 100]["strategy MiniQ^3 -> Stun bomber"]
    +-assemblyFile.line [100, 127]["assert CORESIZE==8000"]
    |  +-assemblyFile.comment [104, 127]["assert CORESIZE==8000"]
    +-assemblyFile.line [128, 149]["org", "", "qGo", ""]
    |  +-assemblyFile.instruction [139, 149]["org", "", "qGo", ""]
    |     +-assemblyFile.operation [139, 142]["org"]
    |     |  +-assemblyFile.opcode [139, 142]["org"]
    |     +-assemblyFile.mode [145, 145][""]
    |     +-assemblyFile.expr [145, 148]["qGo", ""]
    |        +-assemblyFile.term [145, 148]["qGo"]
    |        |  +-assemblyFile.label [145, 148]["qGo"]
    |        +-assemblyFile.tail [148, 148][""]
    +-assemblyFile.line [150, 172]["bStep", "equ", "", "2223", ""]
    |  +-assemblyFile.instruction [154, 172]["bStep", "equ", "", "2223", ""]
    |     +-assemblyFile.label_list [154, 161]["bStep"]
    |     |  +-assemblyFile.label [154, 159]["bStep"]
    |     +-assemblyFile.operation [161, 164]["equ"]
    |     |  +-assemblyFile.opcode [161, 164]["equ"]
    |     +-assemblyFile.mode [167, 167][""]
    |     +-assemblyFile.expr [167, 171]["2223", ""]
    |        +-assemblyFile.term [167, 171]["2223"]
    |        |  +-assemblyFile.number [167, 171]["2223"]
    |        |     +-assemblyFile.whole_number [167, 171]["2223"]
    |        +-assemblyFile.tail [171, 171][""]
    +-assemblyFile.line [172, 193]["bDrop", "equ", "", "382", ""]
    |  +-assemblyFile.instruction [176, 193]["bDrop", "equ", "", "382", ""]
    |     +-assemblyFile.label_list [176, 183]["bDrop"]
    |     |  +-assemblyFile.label [176, 181]["bDrop"]
    |     +-assemblyFile.operation [183, 186]["equ"]
    |     |  +-assemblyFile.opcode [183, 186]["equ"]
    |     +-assemblyFile.mode [189, 189][""]
    |     +-assemblyFile.expr [189, 192]["382", ""]
    |        +-assemblyFile.term [189, 192]["382"]
    |        |  +-assemblyFile.number [189, 192]["382"]
    |        |     +-assemblyFile.whole_number [189, 192]["382"]
    |        +-assemblyFile.tail [192, 192][""]
    +-assemblyFile.line [194, 216]["bDist", "equ", "", "3250", ""]
    |  +-assemblyFile.instruction [198, 216]["bDist", "equ", "", "3250", ""]
    |     +-assemblyFile.label_list [198, 205]["bDist"]
    |     |  +-assemblyFile.label [198, 203]["bDist"]
    |     +-assemblyFile.operation [205, 208]["equ"]
    |     |  +-assemblyFile.opcode [205, 208]["equ"]
    |     +-assemblyFile.mode [211, 211][""]
    |     +-assemblyFile.expr [211, 215]["3250", ""]
    |        +-assemblyFile.term [211, 215]["3250"]
    |        |  +-assemblyFile.number [211, 215]["3250"]
    |        |     +-assemblyFile.whole_number [211, 215]["3250"]
    |        +-assemblyFile.tail [215, 215][""]
    +-assemblyFile.line [216, 236]["bcOff", "equ", "", "51", ""]
    |  +-assemblyFile.instruction [220, 236]["bcOff", "equ", "", "51", ""]
    |     +-assemblyFile.label_list [220, 227]["bcOff"]
    |     |  +-assemblyFile.label [220, 225]["bcOff"]
    |     +-assemblyFile.operation [227, 230]["equ"]
    |     |  +-assemblyFile.opcode [227, 230]["equ"]
    |     +-assemblyFile.mode [233, 233][""]
    |     +-assemblyFile.expr [233, 235]["51", ""]
    |        +-assemblyFile.term [233, 235]["51"]
    |        |  +-assemblyFile.number [233, 235]["51"]
    |        |     +-assemblyFile.whole_number [233, 235]["51"]
    |        +-assemblyFile.tail [235, 235][""]
    +-assemblyFile.line [236, 256]["bgOff", "equ", "", "17", ""]
    |  +-assemblyFile.instruction [240, 256]["bgOff", "equ", "", "17", ""]
    |     +-assemblyFile.label_list [240, 247]["bgOff"]
    |     |  +-assemblyFile.label [240, 245]["bgOff"]
    |     +-assemblyFile.operation [247, 250]["equ"]
    |     |  +-assemblyFile.opcode [247, 250]["equ"]
    |     +-assemblyFile.mode [253, 253][""]
    |     +-assemblyFile.expr [253, 255]["17", ""]
    |        +-assemblyFile.term [253, 255]["17"]
    |        |  +-assemblyFile.number [253, 255]["17"]
    |        |     +-assemblyFile.whole_number [253, 255]["17"]
    |        +-assemblyFile.tail [255, 255][""]
    +-assemblyFile.line [257, 292]["bRun", "equ", "", "(", "bHit", "-", "bInc", "*", "bDrop", "", ")", ""]
    |  +-assemblyFile.instruction [261, 292]["bRun", "equ", "", "(", "bHit", "-", "bInc", "*", "bDrop", "", ")", ""]
    |     +-assemblyFile.label_list [261, 268]["bRun"]
    |     |  +-assemblyFile.label [261, 265]["bRun"]
    |     +-assemblyFile.operation [268, 271]["equ"]
    |     |  +-assemblyFile.opcode [268, 271]["equ"]
    |     +-assemblyFile.mode [274, 274][""]
    |     +-assemblyFile.expr [274, 291]["(", "bHit", "-", "bInc", "*", "bDrop", "", ")", ""]
    |        +-assemblyFile.expr [275, 290]["bHit", "-", "bInc", "*", "bDrop", ""]
    |        |  +-assemblyFile.term [275, 279]["bHit"]
    |        |  |  +-assemblyFile.label [275, 279]["bHit"]
    |        |  +-assemblyFile.tail [279, 290]["-", "bInc", "*", "bDrop", ""]
    |        |     +-assemblyFile.expr [280, 290]["bInc", "*", "bDrop", ""]
    |        |        +-assemblyFile.term [280, 284]["bInc"]
    |        |        |  +-assemblyFile.label [280, 284]["bInc"]
    |        |        +-assemblyFile.tail [284, 290]["*", "bDrop", ""]
    |        |           +-assemblyFile.expr [285, 290]["bDrop", ""]
    |        |              +-assemblyFile.term [285, 290]["bDrop"]
    |        |              |  +-assemblyFile.label [285, 290]["bDrop"]
    |        |              +-assemblyFile.tail [290, 290][""]
    |        +-assemblyFile.tail [291, 291][""]
    +-assemblyFile.line [292, 322]["bGate", "equ", "", "(", "bClr", "-", "bgOff", "", ")", ""]
    |  +-assemblyFile.instruction [296, 322]["bGate", "equ", "", "(", "bClr", "-", "bgOff", "", ")", ""]
    |     +-assemblyFile.label_list [296, 303]["bGate"]
    |     |  +-assemblyFile.label [296, 301]["bGate"]
    |     +-assemblyFile.operation [303, 306]["equ"]
    |     |  +-assemblyFile.opcode [303, 306]["equ"]
    |     +-assemblyFile.mode [309, 309][""]
    |     +-assemblyFile.expr [309, 321]["(", "bClr", "-", "bgOff", "", ")", ""]
    |        +-assemblyFile.expr [310, 320]["bClr", "-", "bgOff", ""]
    |        |  +-assemblyFile.term [310, 314]["bClr"]
    |        |  |  +-assemblyFile.label [310, 314]["bClr"]
    |        |  +-assemblyFile.tail [314, 320]["-", "bgOff", ""]
    |        |     +-assemblyFile.expr [315, 320]["bgOff", ""]
    |        |        +-assemblyFile.term [315, 320]["bgOff"]
    |        |        |  +-assemblyFile.label [315, 320]["bgOff"]
    |        |        +-assemblyFile.tail [320, 320][""]
    |        +-assemblyFile.tail [321, 321][""]
    +-assemblyFile.line [322, 355]["bSpl", "equ", "", "(", "bHit", "-", "2", "*", "bInc", "", ")", "+", "1", ""]
    |  +-assemblyFile.instruction [326, 355]["bSpl", "equ", "", "(", "bHit", "-", "2", "*", "bInc", "", ")", "+", "1", ""]
    |     +-assemblyFile.label_list [326, 333]["bSpl"]
    |     |  +-assemblyFile.label [326, 330]["bSpl"]
    |     +-assemblyFile.operation [333, 336]["equ"]
    |     |  +-assemblyFile.opcode [333, 336]["equ"]
    |     +-assemblyFile.mode [339, 339][""]
    |     +-assemblyFile.expr [339, 354]["(", "bHit", "-", "2", "*", "bInc", "", ")", "+", "1", ""]
    |        +-assemblyFile.expr [340, 351]["bHit", "-", "2", "*", "bInc", ""]
    |        |  +-assemblyFile.term [340, 344]["bHit"]
    |        |  |  +-assemblyFile.label [340, 344]["bHit"]
    |        |  +-assemblyFile.tail [344, 351]["-", "2", "*", "bInc", ""]
    |        |     +-assemblyFile.expr [345, 351]["2", "*", "bInc", ""]
    |        |        +-assemblyFile.term [345, 346]["2"]
    |        |        |  +-assemblyFile.number [345, 346]["2"]
    |        |        |     +-assemblyFile.whole_number [345, 346]["2"]
    |        |        +-assemblyFile.tail [346, 351]["*", "bInc", ""]
    |        |           +-assemblyFile.expr [347, 351]["bInc", ""]
    |        |              +-assemblyFile.term [347, 351]["bInc"]
    |        |              |  +-assemblyFile.label [347, 351]["bInc"]
    |        |              +-assemblyFile.tail [351, 351][""]
    |        +-assemblyFile.tail [352, 354]["+", "1", ""]
    |           +-assemblyFile.expr [353, 354]["1", ""]
    |              +-assemblyFile.term [353, 354]["1"]
    |              |  +-assemblyFile.number [353, 354]["1"]
    |              |     +-assemblyFile.whole_number [353, 354]["1"]
    |              +-assemblyFile.tail [354, 354][""]
    +-assemblyFile.line [355, 388]["bJmp", "equ", "", "(", "bHit", "-", "2", "*", "bInc", "", ")", "-", "1", ""]
    |  +-assemblyFile.instruction [359, 388]["bJmp", "equ", "", "(", "bHit", "-", "2", "*", "bInc", "", ")", "-", "1", ""]
    |     +-assemblyFile.label_list [359, 366]["bJmp"]
    |     |  +-assemblyFile.label [359, 363]["bJmp"]
    |     +-assemblyFile.operation [366, 369]["equ"]
    |     |  +-assemblyFile.opcode [366, 369]["equ"]
    |     +-assemblyFile.mode [372, 372][""]
    |     +-assemblyFile.expr [372, 387]["(", "bHit", "-", "2", "*", "bInc", "", ")", "-", "1", ""]
    |        +-assemblyFile.expr [373, 384]["bHit", "-", "2", "*", "bInc", ""]
    |        |  +-assemblyFile.term [373, 377]["bHit"]
    |        |  |  +-assemblyFile.label [373, 377]["bHit"]
    |        |  +-assemblyFile.tail [377, 384]["-", "2", "*", "bInc", ""]
    |        |     +-assemblyFile.expr [378, 384]["2", "*", "bInc", ""]
    |        |        +-assemblyFile.term [378, 379]["2"]
    |        |        |  +-assemblyFile.number [378, 379]["2"]
    |        |        |     +-assemblyFile.whole_number [378, 379]["2"]
    |        |        +-assemblyFile.tail [379, 384]["*", "bInc", ""]
    |        |           +-assemblyFile.expr [380, 384]["bInc", ""]
    |        |              +-assemblyFile.term [380, 384]["bInc"]
    |        |              |  +-assemblyFile.label [380, 384]["bInc"]
    |        |              +-assemblyFile.tail [384, 384][""]
    |        +-assemblyFile.tail [385, 387]["-", "1", ""]
    |           +-assemblyFile.expr [386, 387]["1", ""]
    |              +-assemblyFile.term [386, 387]["1"]
    |              |  +-assemblyFile.number [386, 387]["1"]
    |              |     +-assemblyFile.whole_number [386, 387]["1"]
    |              +-assemblyFile.tail [387, 387][""]
    +-assemblyFile.line [388, 413]["bInc", "equ", "", "3", "*", "bStep", ""]
    |  +-assemblyFile.instruction [392, 413]["bInc", "equ", "", "3", "*", "bStep", ""]
    |     +-assemblyFile.label_list [392, 399]["bInc"]
    |     |  +-assemblyFile.label [392, 396]["bInc"]
    |     +-assemblyFile.operation [399, 402]["equ"]
    |     |  +-assemblyFile.opcode [399, 402]["equ"]
    |     +-assemblyFile.mode [405, 405][""]
    |     +-assemblyFile.expr [405, 412]["3", "*", "bStep", ""]
    |        +-assemblyFile.term [405, 406]["3"]
    |        |  +-assemblyFile.number [405, 406]["3"]
    |        |     +-assemblyFile.whole_number [405, 406]["3"]
    |        +-assemblyFile.tail [406, 412]["*", "bStep", ""]
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    |              |  +-assemblyFile.label [407, 412]["bStep"]
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    +-assemblyFile.line [414, 451]["bStart", "mov", "i", "{", "0", "", ",", "#", "0", ""]
    |  +-assemblyFile.instruction [418, 451]["bStart", "mov", "i", "{", "0", "", ",", "#", "0", ""]
    |     +-assemblyFile.label_list [418, 425]["bStart"]
    |     |  +-assemblyFile.label [418, 424]["bStart"]
    |     +-assemblyFile.operation [425, 430]["mov", "i"]
    |     |  +-assemblyFile.opcode [425, 428]["mov"]
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    |     |  |  +-assemblyFile.number [432, 433]["0"]
    |     |  |     +-assemblyFile.whole_number [432, 433]["0"]
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    |     +-assemblyFile.mode [448, 449]["#"]
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    +-assemblyFile.line [451, 491]["bLoop", "mov", "", "bSpl", "", ",", "<", "bPtr", ""]
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    |     |  +-assemblyFile.label [455, 460]["bLoop"]
    |     +-assemblyFile.operation [462, 465]["mov"]
    |     |  +-assemblyFile.opcode [462, 465]["mov"]
    |     +-assemblyFile.mode [468, 468][""]
    |     +-assemblyFile.expr [468, 472]["bSpl", ""]
    |     |  +-assemblyFile.term [468, 472]["bSpl"]
    |     |  |  +-assemblyFile.label [468, 472]["bSpl"]
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    |     +-assemblyFile.mode [485, 486]["<"]
    |     +-assemblyFile.expr [486, 490]["bPtr", ""]
    |        +-assemblyFile.term [486, 490]["bPtr"]
    |        |  +-assemblyFile.label [486, 490]["bPtr"]
    |        +-assemblyFile.tail [490, 490][""]
    +-assemblyFile.line [491, 531]["mov", "", "bJmp", "", ",", "*", "bPtr", ""]
    |  +-assemblyFile.instruction [502, 531]["mov", "", "bJmp", "", ",", "*", "bPtr", ""]
    |     +-assemblyFile.operation [502, 505]["mov"]
    |     |  +-assemblyFile.opcode [502, 505]["mov"]
    |     +-assemblyFile.mode [508, 508][""]
    |     +-assemblyFile.expr [508, 512]["bJmp", ""]
    |     |  +-assemblyFile.term [508, 512]["bJmp"]
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    +-assemblyFile.line [531, 579]["bPtr", "mov", "", "bRun", "-", "bStep", "", ",", "@", "bRun", "+", "bStep", "+", "1", ""]
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    |     |  +-assemblyFile.label [535, 539]["bPtr"]
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    |     |  +-assemblyFile.opcode [542, 545]["mov"]
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    |     +-assemblyFile.expr [548, 558]["bRun", "-", "bStep", ""]
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    |     |     +-assemblyFile.expr [553, 558]["bStep", ""]
    |     |        +-assemblyFile.term [553, 558]["bStep"]
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    |     +-assemblyFile.expr [566, 578]["bRun", "+", "bStep", "+", "1", ""]
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    |           +-assemblyFile.expr [571, 578]["bStep", "+", "1", ""]
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    |              |  +-assemblyFile.label [571, 576]["bStep"]
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    |                 +-assemblyFile.expr [577, 578]["1", ""]
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    |                    |  +-assemblyFile.number [577, 578]["1"]
    |                    |     +-assemblyFile.whole_number [577, 578]["1"]
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    +-assemblyFile.line [579, 618]["bHit", "add", "*", "bEvac", "", ",", "", "bPtr", ""]
    |  +-assemblyFile.instruction [583, 618]["bHit", "add", "*", "bEvac", "", ",", "", "bPtr", ""]
    |     +-assemblyFile.label_list [583, 590]["bHit"]
    |     |  +-assemblyFile.label [583, 587]["bHit"]
    |     +-assemblyFile.operation [590, 593]["add"]
    |     |  +-assemblyFile.opcode [590, 593]["add"]
    |     +-assemblyFile.mode [596, 597]["*"]
    |     +-assemblyFile.expr [597, 602]["bEvac", ""]
    |     |  +-assemblyFile.term [597, 602]["bEvac"]
    |     |  |  +-assemblyFile.label [597, 602]["bEvac"]
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    |     +-assemblyFile.mode [613, 613][""]
    |     +-assemblyFile.expr [613, 617]["bPtr", ""]
    |        +-assemblyFile.term [613, 617]["bPtr"]
    |        |  +-assemblyFile.label [613, 617]["bPtr"]
    |        +-assemblyFile.tail [617, 617][""]
    +-assemblyFile.line [618, 658]["mov", ">", "bJmp", "", ",", "@", "bPtr", ""]
    |  +-assemblyFile.instruction [629, 658]["mov", ">", "bJmp", "", ",", "@", "bPtr", ""]
    |     +-assemblyFile.operation [629, 632]["mov"]
    |     |  +-assemblyFile.opcode [629, 632]["mov"]
    |     +-assemblyFile.mode [635, 636][">"]
    |     +-assemblyFile.expr [636, 640]["bJmp", ""]
    |     |  +-assemblyFile.term [636, 640]["bJmp"]
    |     |  |  +-assemblyFile.label [636, 640]["bJmp"]
    |     |  +-assemblyFile.tail [640, 640][""]
    |     +-assemblyFile.mode [652, 653]["@"]
    |     +-assemblyFile.expr [653, 657]["bPtr", ""]
    |        +-assemblyFile.term [653, 657]["bPtr"]
    |        |  +-assemblyFile.label [653, 657]["bPtr"]
    |        +-assemblyFile.tail [657, 657][""]
    +-assemblyFile.line [658, 698]["jmz", "a", "", "bLoop", "", ",", "<", "bJmp", ""]
    |  +-assemblyFile.instruction [669, 698]["jmz", "a", "", "bLoop", "", ",", "<", "bJmp", ""]
    |     +-assemblyFile.operation [669, 674]["jmz", "a"]
    |     |  +-assemblyFile.opcode [669, 672]["jmz"]
    |     |  +-assemblyFile.modifier [673, 674]["a"]
    |     +-assemblyFile.mode [675, 675][""]
    |     +-assemblyFile.expr [675, 680]["bLoop", ""]
    |     |  +-assemblyFile.term [675, 680]["bLoop"]
    |     |  |  +-assemblyFile.label [675, 680]["bLoop"]
    |     |  +-assemblyFile.tail [680, 680][""]
    |     +-assemblyFile.mode [692, 693]["<"]
    |     +-assemblyFile.expr [693, 697]["bJmp", ""]
    |        +-assemblyFile.term [693, 697]["bJmp"]
    |        |  +-assemblyFile.label [693, 697]["bJmp"]
    |        +-assemblyFile.tail [697, 697][""]
    +-assemblyFile.EOF (failure)
       +-negLookahead!(any) failure at line 29, col 0, after "  , <bJmp
" expected anything but " ", but got "    bEvac "

No segfault, but a missing :WS? maybe?

SuperDoxin commented 8 years ago

well don't I look silly. in my debugging attempts I was using an old grammar by accident. that said, I am still intermittently getting warnings about unreachable code. I have turned off generating errors for warnings for now.

veelo commented 8 years ago

OK. I suppose you could get unreachable code if your grammar contains a rule that is nowhere used in the rest of the grammar (and it's not the first one).

SuperDoxin commented 8 years ago

it seems the unreachability-ness is related to the if(__ctfe) statements, which would make sense I guess.

veelo commented 8 years ago

Ah. Food for the forum?

PhilippeSigaud commented 8 years ago

On Thu, Feb 4, 2016 at 11:33 PM, Bastiaan Veelo notifications@github.com wrote

Doxin, if you ever get an 'unreachable statement' warning with a small grammar, I'm interested in diving in the generated source code.

SuperDoxin commented 8 years ago

depends on your definition of small. this grammar throws two such warnings

dlang-community / Pegged

segfault on parsing some inputs #182