From e355cd6cbf2b62be98b1206d33d79073cadf1174 Mon Sep 17 00:00:00 2001
From: Jean Privat <jean@pryen.org>
Date: Sat, 29 Jun 2024 08:46:13 -0400
Subject: [PATCH] nitcc: add to_dot_lr0 that draws a lr0 automaton without much
 annontation

Signed-off-by: Jean Privat <jean@pryen.org>
---
 contrib/nitcc/src/grammar.nit | 33 +++++++++++++++++++++++++++++++++
 contrib/nitcc/src/nitcc.nit   |  3 ++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/contrib/nitcc/src/grammar.nit b/contrib/nitcc/src/grammar.nit
index 3484d0a505..0ddb646c73 100644
--- a/contrib/nitcc/src/grammar.nit
+++ b/contrib/nitcc/src/grammar.nit
@@ -589,6 +589,39 @@ class LRAutomaton
 		return res.join
 	end
 
+	# Generate a graphviz file of the automaton
+	# This generate a simple executable LR0 without much information
+	fun to_dot_lr0(path: String)
+	do
+		var f = new FileWriter.open(path)
+		f.write("digraph \{\n")
+		f.write("rankdir=TB;\n")
+		f.write("node[shape=box,style=rounded];\n")
+
+		f.write("entry [style=invis];\nentry -> s{states.first.number}\n")
+		for s in states do
+			f.write "s{s.number} [label=\""
+			for a in s.reduces do
+				if a.prod.accept then
+					f.write "ACCEPT\\n"
+				else
+					f.write "REDUCE {a.prod.name.escape_to_dot} WITH {a.elems.length} ELEMENTS\\n"
+				end
+			end
+			if s.shifts.length > 0 then
+				f.write "SHIFT\\n"
+			end
+			f.write "\""
+			if not s.is_lr0 then f.write ",color=red"
+			f.write "];\n"
+			for t in s.outs do
+				f.write "s{s.number} -> s{t.to.number} [label=\"{t.elem.to_s.escape_to_dot}\"];\n"
+			end
+		end
+		f.write("\}\n")
+		f.close
+	end
+
 	# Generate a graphviz file of the automaton
 	fun to_dot(path: String)
 	do
diff --git a/contrib/nitcc/src/nitcc.nit b/contrib/nitcc/src/nitcc.nit
index a54044bac3..aa2e98abb2 100644
--- a/contrib/nitcc/src/nitcc.nit
+++ b/contrib/nitcc/src/nitcc.nit
@@ -99,8 +99,9 @@ f.write "// Concrete grammar of {name}\n"
 f.write pretty
 f.close
 
-print "LR automaton: {lr.states.length} states (see {name}.lr.dot and {name}.lr.out)"
+print "LR automaton: {lr.states.length} states (see {name}.lr.dot, {name}.lr0.dot and {name}.lr.out)"
 lr.to_dot("{name}.lr.dot")
+lr.to_dot_lr0("{name}.lr0.dot")
 pretty = lr.pretty
 f = new FileWriter.open("{name}.lr.out")
 f.write "// LR automaton of {name}\n"