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“I made a program to generate dot files representing the LR(0) state graph along with computed LALR(1) lookahead for an arbitrary context-free grammar, to make the diagrams I used in this article: http://blog.lab49.com/archives/2471. The program also highlights errant nodes in red if the grammar would produce a shift/reduce or reduce/reduce conflict – you may be able to go to http://kthielen.dnsalias.com:8082/ to produce a graph more to your liking”. Contributed by Kalani Thielen.

[Input .gv File] [SVG] [Raster Image] [Open in Playground]

##"I made a program to generate dot files representing the LR(0) state graph along with computed LALR(1) lookahead for an arbitrary context-free grammar, to make the diagrams I used in this article: http://blog.lab49.com/archives/2471. The program also highlights errant nodes in red if the grammar would produce a shift/reduce or reduce/reduce conflict -- you may be able to go to http://kthielen.dnsalias.com:8082/ to produce a graph more to your liking". Contributed by Kalani Thielen.

##Command to get the layout: "dot -Gsize=10,15 -Tpng thisfile > thisfile.png"

digraph g {
  graph [fontsize=30 labelloc="t" label="" splines=true overlap=false rankdir = "LR"];
  ratio = auto;
  "state0" [ style = "filled, bold" penwidth = 5 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #0</font></td></tr><tr><td align="left" port="r0">&#40;0&#41; s -&gt; &bull;e $ </td></tr><tr><td align="left" port="r1">&#40;1&#41; e -&gt; &bull;l '=' r </td></tr><tr><td align="left" port="r2">&#40;2&#41; e -&gt; &bull;r </td></tr><tr><td align="left" port="r3">&#40;3&#41; l -&gt; &bull;'*' r </td></tr><tr><td align="left" port="r4">&#40;4&#41; l -&gt; &bull;'n' </td></tr><tr><td align="left" port="r5">&#40;5&#41; r -&gt; &bull;l </td></tr></table>> ];
  "state1" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #1</font></td></tr><tr><td align="left" port="r3">&#40;3&#41; l -&gt; &bull;'*' r </td></tr><tr><td align="left" port="r3">&#40;3&#41; l -&gt; '*' &bull;r </td></tr><tr><td align="left" port="r4">&#40;4&#41; l -&gt; &bull;'n' </td></tr><tr><td align="left" port="r5">&#40;5&#41; r -&gt; &bull;l </td></tr></table>> ];
  "state2" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #2</font></td></tr><tr><td align="left" port="r4">&#40;4&#41; l -&gt; 'n' &bull;</td><td bgcolor="grey" align="right">=$</td></tr></table>> ];
  "state3" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #3</font></td></tr><tr><td align="left" port="r5">&#40;5&#41; r -&gt; l &bull;</td><td bgcolor="grey" align="right">=$</td></tr></table>> ];
  "state4" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #4</font></td></tr><tr><td align="left" port="r3">&#40;3&#41; l -&gt; '*' r &bull;</td><td bgcolor="grey" align="right">=$</td></tr></table>> ];
  "state5" [ style = "filled" penwidth = 1 fillcolor = "black" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="black"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #5</font></td></tr><tr><td align="left" port="r0"><font color="white">&#40;0&#41; s -&gt; e &bull;$ </font></td></tr></table>> ];
  "state6" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #6</font></td></tr><tr><td align="left" port="r1">&#40;1&#41; e -&gt; l &bull;'=' r </td></tr><tr><td align="left" port="r5">&#40;5&#41; r -&gt; l &bull;</td><td bgcolor="grey" align="right">$</td></tr></table>> ];
  "state7" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #7</font></td></tr><tr><td align="left" port="r1">&#40;1&#41; e -&gt; l '=' &bull;r </td></tr><tr><td align="left" port="r3">&#40;3&#41; l -&gt; &bull;'*' r </td></tr><tr><td align="left" port="r4">&#40;4&#41; l -&gt; &bull;'n' </td></tr><tr><td align="left" port="r5">&#40;5&#41; r -&gt; &bull;l </td></tr></table>> ];
  "state8" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #8</font></td></tr><tr><td align="left" port="r1">&#40;1&#41; e -&gt; l '=' r &bull;</td><td bgcolor="grey" align="right">$</td></tr></table>> ];
  "state9" [ style = "filled" penwidth = 1 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<<table border="0" cellborder="0" cellpadding="3" bgcolor="white"><tr><td bgcolor="black" align="center" colspan="2"><font color="white">State #9</font></td></tr><tr><td align="left" port="r2">&#40;2&#41; e -&gt; r &bull;</td><td bgcolor="grey" align="right">$</td></tr></table>> ];
  state0 -> state5 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "e" ];
  state0 -> state6 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "l" ];
  state0 -> state9 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "r" ];
  state0 -> state1 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'*'" ];
  state0 -> state2 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'n'" ];
  state1 -> state1 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'*'" ];
  state1 -> state4 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "r" ];
  state1 -> state2 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'n'" ];
  state1 -> state3 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "l" ];
  state6 -> state7 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'='" ];
  state7 -> state8 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "r" ];
  state7 -> state1 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'*'" ];
  state7 -> state2 [ penwidth = 1 fontsize = 14 fontcolor = "grey28" label = "'n'" ];
  state7 -> state3 [ penwidth = 5 fontsize = 28 fontcolor = "black" label = "l" ];
}

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