[SyntaxTree] Proposition of new tree dump

[eduucaldas]

Summary

Some key choices to highlight:

• Surround Tokens with '
• Do not print UnknownRole, to reduce noise
• Surround Roles with <, to clarify the difference in meaning

[gribozavr2]

I'd suggest to drop the <> quotes (because the AST dump does not add quotes unless it is printing a multi-word thing, and because <> don't exactly scream "role" helping to read the output).

I'd also suggest to replace multiple spaces before <> with a single space.

Otherwise, looks great!

[eduucaldas]

Answering comments

[gribozavr2]

LGTM!

[eduucaldas]

Reflect comments

[eduucaldas]

clang/unittests/Tooling/Syntax/TreeTest.cpp

3381

Some points to make a decision.
What should be the order of these extra information?
I like the order now, Most frequent in the left.

More decriptive markers?
We could choose to have more descriptive markers
I -> unmodifieable
M-> not backed by source code / synthesized

Ambiguity.
Since we choose to not dump a role for NodeRole::Unknown we might have some ambiguity between NodeRoles and markers. We can avoid that by surrounding markers, or making them lower-case. or even by just leaving one character markers

clang/unittests/Tooling/Syntax/TreeTest.cpp

TEST_P(SyntaxTreeTest, If) {
   EXPECT_TRUE(treeDumpEqual(
       R"cpp(
 int main() {
   if (1) {}
   if (1) {} else if (0) {}
 }
 )cpp",
       R"txt(
-*: TranslationUnit
+TranslationUnit Detached
 `-SimpleDeclaration
-  |-int
-  |-SimpleDeclarator
-  | |-main
-  | `-ParametersAndQualifiers
-  |   |-(
-  |   `-)
-  `-CompoundStatement
-    |-{
-    |-IfStatement
-    | |-if
-    | |-(
+  |-'int'
+  |-SimpleDeclarator SimpleDeclaration_declarator
+  | |-'main'
+  | `-ParametersAndQualifiers
+  |   |-'(' OpenParen
+  |   `-')' CloseParen
+  `-CompoundStatement
+    |-'{' OpenParen
+    |-IfStatement CompoundStatement_statement
+    | |-'if' IntroducerKeyword
+    | |-'('
     | |-IntegerLiteralExpression
-    | | `-1
-    | |-)
-    | `-CompoundStatement
-    |   |-{
-    |   `-}
-    |-IfStatement
-    | |-if
-    | |-(
+    | | `-'1' LiteralToken
+    | |-')'
+    | `-CompoundStatement IfStatement_thenStatement
+    |   |-'{' OpenParen
+    |   `-'}' CloseParen
+    |-IfStatement CompoundStatement_statement
+    | |-'if' IntroducerKeyword
+    | |-'('
     | |-IntegerLiteralExpression
-    | | `-1
-    | |-)
-    | |-CompoundStatement
-    | | |-{
-    | | `-}
-    | |-else
-    | `-IfStatement
-    |   |-if
-    |   |-(
+    | | `-'1' LiteralToken
+    | |-')'
+    | |-CompoundStatement IfStatement_thenStatement
+    | | |-'{' OpenParen
+    | | `-'}' CloseParen
+    | |-'else' IfStatement_elseKeyword
+    | `-IfStatement IfStatement_elseStatement
+    |   |-'if' IntroducerKeyword
+    |   |-'('
     |   |-IntegerLiteralExpression
-    |   | `-0
-    |   |-)
-    |   `-CompoundStatement
-    |     |-{
-    |     `-}
-    `-}
+    |   | `-'0' LiteralToken
+    |   |-')'
+    |   `-CompoundStatement IfStatement_thenStatement
+    |     |-'{' OpenParen
+    |     `-'}' CloseParen
+    `-'}' CloseParen
 )txt"));
 }
 
 TEST_P(SyntaxTreeTest, For) {
   EXPECT_TRUE(treeDumpEqual(
       R"cpp(
 void test() {
   for (;;)  {}
`-CompoundStatement
     | | `-I: }
     | |-else
     | `-CompoundStatement
     |   |-{
     |   `-}
     `-}
 )txt"));
 }
 
 TEST_P(SyntaxTreeTest, ModifiableNodes) {
   // All nodes can be mutated.
   EXPECT_TRUE(treeDumpEqual(
       R"cpp(
 #define OPEN {
 #define CLOSE }
 
 void test() {