1 files changed, 128 insertions, 0 deletions
diff --git a/nfa/nfa-to-latex.py b/nfa/nfa-to-latex.py
new file mode 100755
index 0000000..fb3a540
--- /dev/null
+++ b/nfa/nfa-to-latex.py
@@ -0,0 +1,128 @@
+#!/usr/bin/env python
+# Usage:
+#   <z3-output.txt ./nfa-to-latex.py dot |
+#   dot -Txdot /dev/stdin | dot2tex -f tikz --figonly | sed s/ellipse/circle/ > some.tex
+import sys
+
+draw_dot = False if len(sys.argv) <= 1 else sys.argv[1] == "dot"
+
+in_block = None
+transitions = {}
+finals = []
+
+for line in sys.stdin:
+    line = line.strip()
+    if line == "unsat":
+        sys.exit('unsat!')
+    if line == "sat":
+        continue
+
+    # End of array
+    if line == "}":
+        in_block = None
+        continue
+
+    key, val = line.split(" -> ")
+    if key[0] in "sq":
+        # Skip the internal, non-optimized states that were used for tracking
+        # the letters. Skip also the state variables (just used for tracking).
+        continue
+
+    # Enter block
+    if key in ("trans", "final"):
+        in_block = key
+        continue
+
+    # Do not care
+    if key == "else":
+        continue
+
+    # Skip garbage like "(- 5905) 0 -> (- 2998)"
+    if "(-" in line:
+        continue
+
+    if in_block == "trans":
+        # Example input:
+        # trans -> {
+        #   0 0 -> 1
+        #   2 0 -> 1
+        #   else -> 1
+        # }
+        state_prev, letter_number = map(int, key.split())
+        state_next = int(val)
+        letter = "ab"[letter_number]
+        if (state_prev, state_next) not in transitions:
+            transitions[state_prev, state_next] = ""
+        transitions[state_prev, state_next] += letter
+    elif in_block == "final":
+        # Example input:
+        # final -> {
+        #   2 -> true
+        #   3 -> false
+        #   else -> false
+        # }
+        state = int(key)
+        is_final = val == "true"
+        while len(finals) <= state:
+            finals.append(None)
+        finals[state] = is_final
+    else:
+        raise RuntimeError("Unexpected reading state at line: %s" % line)
+
+m = len(finals)
+
+if draw_dot:
+    nodes = ""
+    edges = ""
+    # Nodes
+    for i in range(m):
+        line = "node [shape=%scircle];" % ("double" if finals[i] else "")
+        line += " q%d;" % i
+        nodes += "    %s\n" % line
+    # Transitions
+    for (state_prev, state_next), label in transitions.items():
+        line = "q%d -> q%d" % (state_prev, state_next)
+        line += " [label=\"%s\"];" % ", ".join(label)
+        edges += "    %s\n" % line
+    dot_source = """digraph nfa {{
+    rankdir=LR;
+    size="8,5";
+
+    # Incoming arrow
+    node [shape=point]; qi;
+    {nodes}
+
+    qi -> q0;
+    {edges}
+}}""".format(nodes=nodes, edges=edges)
+    print(dot_source)
+else:
+    # See http://tex.stackexchange.com/a/20786
+    # \usetikzlibrary{automata,positioning}
+    # \begin{tikzpicture}[shorten >=1pt,node distance=2cm,on grid,auto]
+    # Draw nodes
+    for i in range(m):
+        line = r"\node[state"
+        if i == 0:
+            line += ",initial"
+        if finals[i]:
+            line += ",accepting"
+        line += "]"
+        line = line.ljust(24)
+        line += " (q%d)" % i
+        # XXX autopositioning is not working! Need things like "[right of=q0]"
+        # below/above left/right
+        if i > 0:
+            line += " [right of=q0]"
+        line = line.ljust(52)
+        line += " {$q_%s$}" % i
+        line += ";"
+        print(line)
+
+    print(r"\path[->]")
+
+    # Draw edges with labels
+    for (state_prev, state_next), label in transitions.items():
+        line = "(q%d) edge node {%s} (q%d)" % (state_prev, label, state_next)
+        print(line)
+    print(";")