Improve astprinter #2847 from privat

The module `astprinter` is used to print AST in order to debug synthetic statements and expressions.
It was quite limited.

This PR extends it to most Nit expressions and statements. The missing ones will be addressed in futures PR.

The PR also add a simple nit test program `syntax_expr.nit` that exhibits many syntactic constructions. It is used to test the astprinter through a test tool `test_astprinter` that (pretty?)-print given programs.

src/test_astprinter.nit

@@ -0,0 +1,37 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Test the AST printer by reading modules and printing the body of their methods
+module test_astprinter
+
+import test_phase
+import frontend
+#import transform # Not yet :)
+
+import astprinter
+
+redef fun do_work(mainmodule, given_mmodules, modelbuilder)
+do
+	# We iterate the model instead of the ast for classes and methods
+	for m in given_mmodules do
+		for cd in m.mclassdefs do
+			for pd in cd.mpropdefs do
+				print "# {pd}"
+				var node = modelbuilder.mentity2node(pd)
+				assert node != null
+				node.print_tree
+			end
+		end
+	end
+end

tests/nitcg.skip

@@ -10,3 +10,4 @@ test_loader
 get_mclasses
 ^nit
 test_astbuilder
+test_astprinter

tests/niti.skip

@@ -47,3 +47,4 @@ repeating_key_xor_solve
 nitpm
 nitdoc
 test_astbuilder
+test_astprinter

tests/sav/syntax_expr.res

@@ -0,0 +1,2 @@
+1
+1

tests/sav/test_astprinter.res

@@ -0,0 +1,2 @@
+Usage: [OPTION]... <file.nit>...
+Use --help for help

tests/sav/test_astprinter_args1.res

@@ -0,0 +1,87 @@
+# syntax_expr$Sys$main
+var a
+var b: Bool
+var c: Collection[Int] = [1]
+var d = 1
+a = 1.+(2).-(3.unary -./(4).*(5).%(6.**(2)))
+b = true and not false or true or a.<(0) or a.<=(0) or a.==(0) or a.!=(0) or a.>=(0) or a.>(0)
+a = 1.&(2).|(3.unary ~.^(4.<<(5).>>(6)))
+a = 1.<=>(2)
+c = [1..2[
+c = [1..2]
+c = [1, 2, 3]
+a += 1
+a -= 1
+a *= 1
+a /= 1
+a %= 1
+a **= 1
+a &= 1
+a |= 1
+a ^= 1
+a <<= 1
+a >>= 1
+a = 1
+print(a)
+print(a)
+a.abs
+a.max(2)
+a.max(2)
+a.setbit(0, 1)
+c = new Array[Int].defaultinit
+c = new Array[Int].with_capacity(10)
+a = new Array[Int].with_capacity(10).length
+c.add(1)
+a = a isa Array[Int]
+a = null
+if b then a = 1
+d = a.as(not null)
+d = a.as(Int)
+do end
+do a = 1
+do
+	a = 1
+	a = 1
+end
+if b then end
+if b then a = 1
+if b then
+	a = 2
+	a = 2
+end
+if b then a = 3
+if b then a = 4 else a = 5
+if b then a = 6 else
+	a = 7
+	a = 7
+end
+if b then end
+if b then end
+if b then else a = 8
+if b then else
+	a = 9
+	a = 9
+end
+if b then if b then a = 1
+if b then
+	if b then
+		a = 2
+		a = 3
+	end
+end
+a = if b then 1 else 2
+a = if b then if b then 3 else 4 else if b then 5 else 6
+for i in c do end
+for i in c do
+	a = 1
+	a = 1
+end
+for i in c, j in c do end
+var m = new HashMap[String, String].defaultinit
+for k, v in m do end
+loop
+	if b then break
+	if b then continue
+end
+assert b
+if not b then return 

tests/syntax_expr.nit

@@ -0,0 +1,118 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+var a
+var b: Bool
+var c: Collection[Int] = [1]
+var d = 1
+a = 1 + 2 - - 3 / 4 * 5 % 6 ** 2
+b = true and not false or true or a < 0 or a <= 0 or a == 0 or a != 0 or a >= 0 or a > 0
+a = 1 & 2 | ~3 ^ 4 << 5 >> 6
+a = 1 <=> 2
+c = [1..2[
+c = [1..2]
+c = [1,2,3]
+
+a += 1
+a -= 1
+a *= 1
+a /= 1
+a %= 1
+a **= 1
+
+a &= 1
+a |= 1
+a ^= 1
+a <<= 1
+a >>= 1
+
+a = 1
+print(a)
+print a
+a.abs
+a.max(2)
+a.max 2
+a.setbit(0, 1)
+
+c = new Array[Int]
+c = new Array[Int].with_capacity(10)
+a = new Array[Int].with_capacity(10).length
+c.add(1)
+
+a = a isa Array[Int]
+a = null
+if b then a = 1
+d = a.as(not null)
+d = a.as(Int)
+
+
+do end
+do a = 1
+do
+	a = 1
+	a = 1
+end
+
+if b then end
+if b then a = 1
+if b then
+	a = 2
+	a = 2
+end
+if b then a = 3 else end
+if b then a = 4 else a = 5
+if b then a = 6 else
+	a = 7
+	a = 7
+end
+if b then
+else
+end
+if b then else end
+if b then else a = 8
+if b then else
+	a = 9
+	a = 9
+end
+if b then
+	if b then
+		a = 1
+	end
+end
+if b then
+	if b then
+		a = 2
+		a = 3
+	end
+end
+
+a = if b then 1 else 2
+a = if b then if b then 3 else 4 else if b then 5 else 6
+
+for i in c do end
+for i in c do
+	a = 1
+	a = 1
+end
+for i in c, j in c do end
+var m = new HashMap[String,String]
+for k, v in m do end
+
+loop
+	if b then break
+	if b then continue
+end
+
+assert b
+if not b then return

tests/test_astprinter.args

@@ -0,0 +1 @@
+syntax_expr.nit