Subject: [PATCH v3 0/6] Fun with cpp word regex

From: "Johannes Sixt via GitGitGadget" <[email-masked]>
Date: Sun, 10 Oct 2021 17:02:58 +0000

The cpp word regex driver is a bit too loose and can match too much text
where the intent is to match only a number.

The first patch makes the cpp word regex tests more effective.

The second patch adds problematic test cases. The third patch fixes these
problems.

The remaining three patches add support for digit separators and the
spaceship operator <=> (generalized comparison operator).

I left out support for hexadecimal floating point constants because that
would require to tighten the regex even more to avoid that entire
expressions are treated as single tokens.

Changes since V2:

 * Add test cases for the new features in a separate commit so that the new
   behavior is better visible.
 * Don't treat .' as in '.' as a token.

Changes since V1:

 * Tests, tests, tests.
 * Polished commit messages.

Johannes Sixt (6):
  t4034/cpp: actually test that operator tokens are not split
  t4034: add tests showing problematic cpp tokenizations
  userdiff-cpp: tighten word regex
  userdiff-cpp: prepare test cases with yet unsupported features
  userdiff-cpp: permit the digit-separating single-quote in numbers
  userdiff-cpp: learn the C++ spaceship operator

 t/t4034/cpp/expect | 63 +++++++++++++++++++++++-----------------------
 t/t4034/cpp/post   | 47 +++++++++++++++++++++-------------
 t/t4034/cpp/pre    | 41 +++++++++++++++++++-----------
 userdiff.c         | 10 ++++++--
 4 files changed, 94 insertions(+), 67 deletions(-)

base-commit: 225bc32a989d7a22fa6addafd4ce7dcd04675dbf
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1054%2Fj6t%2Ffun-with-cpp-word-regex-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1054/j6t/fun-with-cpp-word-regex-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/1054

Range-diff vs v2:

 1:  dd9f82ba712 = 1:  dd9f82ba712 t4034/cpp: actually test that operator tokens are not split
 2:  5a84fc9cf71 = 2:  5a84fc9cf71 t4034: add tests showing problematic cpp tokenizations
 3:  d4ebe45fddc = 3:  d4ebe45fddc userdiff-cpp: tighten word regex
 4:  dd75d19cee9 ! 4:  c9f58b5e82f userdiff-cpp: permit the digit-separating single-quote in numbers
     @@ Metadata
      Author: Johannes Sixt <[email-masked]>
      
       ## Commit message ##
     -    userdiff-cpp: permit the digit-separating single-quote in numbers
     +    userdiff-cpp: prepare test cases with yet unsupported features
      
     -    Since C++17, the single-quote can be used as digit separator:
     -
     -       3.141'592'654
     -       1'000'000
     -       0xdead'beaf
     -
     -    Make it known to the word regex of the cpp driver, so that numbers are
     -    not split into separate tokens at the single-quotes.
     +    We are going to add support for C++'s digit-separating single-quote and
     +    the spaceship operator. By adding the test cases in this separate
     +    commit, the effect on the word highlighting will become more obvious
     +    as the features are implemented and the file cpp/expect is updated.
      
          Signed-off-by: Johannes Sixt <[email-masked]>
      
     @@ t/t4034/cpp/expect
      @@
       <BOLD>diff --git a/pre b/post<RESET>
      -<BOLD>index 1229cdb..3feae6f 100644<RESET>
     -+<BOLD>index 60f3640..f6fbf7b 100644<RESET>
     ++<BOLD>index 144cd98..64e78af 100644<RESET>
       <BOLD>--- a/pre<RESET>
       <BOLD>+++ b/post<RESET>
       <CYAN>@@ -1,30 +1,30 @@<RESET>
     -@@ t/t4034/cpp/expect: Foo() : x(0<RED>&&1<RESET><GREEN>&42<RESET>) { <RED>foo0<RESET><GREEN>bar<RESET>
     + Foo() : x(0<RED>&&1<RESET><GREEN>&42<RESET>) { <RED>foo0<RESET><GREEN>bar<RESET>(x.<RED>find<RESET><GREEN>Find<RESET>); }
       cout<<"Hello World<RED>!<RESET><GREEN>?<RESET>\n"<<endl;
     - <GREEN>(<RESET>1 <RED>-<RESET><GREEN>+<RESET>1e10 0xabcdef<GREEN>)<RESET> '<RED>x<RESET><GREEN>y<RESET>'
     +-<GREEN>(<RESET>1 <RED>-<RESET><GREEN>+<RESET>1e10 0xabcdef<GREEN>)<RESET> '<RED>x<RESET><GREEN>y<RESET>'
     ++<GREEN>(<RESET>1 <RED>-<RESET><GREEN>+<RESET>1e10 0xabcdef<GREEN>)<RESET> '<RED>x<RESET><GREEN>.<RESET>'
       // long double<RESET>
      -<RED>3.141592653e-10l<RESET><GREEN>3.141592654e+10l<RESET>
     -+<RED>3.141'592'653e-10l<RESET><GREEN>3.141'592'654e+10l<RESET>
     ++3.141'592'<RED>653e-10l<RESET><GREEN>654e+10l<RESET>
       // float<RESET>
       <RED>120E5f<RESET><GREEN>120E6f<RESET>
       // hex<RESET>
      -<RED>0xdeadbeaf<RESET><GREEN>0xdeadBeaf<RESET>+<RED>8ULL<RESET><GREEN>7ULL<RESET>
     -+<RED>0xdead'beaf<RESET><GREEN>0xdead'Beaf<RESET>+<RED>8ULL<RESET><GREEN>7ULL<RESET>
     ++0xdead'<RED>beaf<RESET><GREEN>Beaf<RESET>+<RED>8ULL<RESET><GREEN>7ULL<RESET>
       // octal<RESET>
      -<RED>01234567<RESET><GREEN>01234560<RESET>
     -+<RED>0123'4567<RESET><GREEN>0123'4560<RESET>
     ++0123'<RED>4567<RESET><GREEN>4560<RESET>
       // binary<RESET>
      -<RED>0b1000<RESET><GREEN>0b1100<RESET>+e1
     -+<RED>0b10'00<RESET><GREEN>0b11'00<RESET>+e1
     ++<RED>0b10<RESET><GREEN>0b11<RESET>'00+e1
       // expression<RESET>
       1.5-e+<RED>2<RESET><GREEN>3<RESET>+f
       // another one<RESET>
     +@@ t/t4034/cpp/expect: str.e+<RED>65<RESET><GREEN>75<RESET>
     + a<RED>*<RESET><GREEN>*=<RESET>b c<RED>/<RESET><GREEN>/=<RESET>d e<RED>%<RESET><GREEN>%=<RESET>f
     + a<RED>+<RESET><GREEN>++<RESET>b c<RED>-<RESET><GREEN>--<RESET>d
     + a<RED><<<RESET><GREEN><<=<RESET>b c<RED>>><RESET><GREEN>>>=<RESET>d
     +-a<RED><<RESET><GREEN><=<RESET>b c<RED><=<RESET><GREEN><<RESET>d e<RED>><RESET><GREEN>>=<RESET>f g<RED>>=<RESET><GREEN>><RESET>h
     ++a<RED><<RESET><GREEN><=<RESET>b c<RED><=<RESET><GREEN><<RESET>d e<RED>><RESET><GREEN>>=<RESET>f g<RED>>=<RESET><GREEN>><RESET>h i<=<GREEN>><RESET>j
     + a<RED>==<RESET><GREEN>!=<RESET>b c<RED>!=<RESET><GREEN>=<RESET>d
     + a<RED>^<RESET><GREEN>^=<RESET>b c<RED>|<RESET><GREEN>|=<RESET>d e<RED>&&<RESET><GREEN>&=<RESET>f
     + a<RED>||<RESET><GREEN>|<RESET>b
      
       ## t/t4034/cpp/post ##
     -@@ t/t4034/cpp/post: Foo() : x(0&42) { bar(x.Find); }
     +@@
     + Foo() : x(0&42) { bar(x.Find); }
       cout<<"Hello World?\n"<<endl;
     - (1 +1e10 0xabcdef) 'y'
     +-(1 +1e10 0xabcdef) 'y'
     ++(1 +1e10 0xabcdef) '.'
       // long double
      -3.141592654e+10l
      +3.141'592'654e+10l
     @@ t/t4034/cpp/post: Foo() : x(0&42) { bar(x.Find); }
       // expression
       1.5-e+3+f
       // another one
     +@@ t/t4034/cpp/post: str.e+75
     + a*=b c/=d e%=f
     + a++b c--d
     + a<<=b c>>=d
     +-a<=b c<d e>=f g>h
     ++a<=b c<d e>=f g>h i<=>j
     + a!=b c=d
     + a^=b c|=d e&=f
     + a|b
      
       ## t/t4034/cpp/pre ##
      @@ t/t4034/cpp/pre: Foo():x(0&&1){ foo0( x.find); }
     @@ t/t4034/cpp/pre: Foo():x(0&&1){ foo0( x.find); }
       // expression
       1.5-e+2+f
       // another one
     -
     - ## userdiff.c ##
     -@@ userdiff.c: PATTERNS("cpp",
     - 	 /* identifiers and keywords */
     - 	 "[a-zA-Z_][a-zA-Z0-9_]*"
     - 	 /* decimal and octal integers as well as floatingpoint numbers */
     --	 "|[0-9][0-9.]*([Ee][-+]?[0-9]+)?[fFlLuU]*"
     -+	 "|[0-9][0-9.']*([Ee][-+]?[0-9]+)?[fFlLuU]*"
     - 	 /* hexadecimal and binary integers */
     --	 "|0[xXbB][0-9a-fA-F]+[lLuU]*"
     -+	 "|0[xXbB][0-9a-fA-F']+[lLuU]*"
     - 	 /* floatingpoint numbers that begin with a decimal point */
     --	 "|\\.[0-9]+([Ee][-+]?[0-9]+)?[fFlL]?"
     -+	 "|\\.[0-9']+([Ee][-+]?[0-9]+)?[fFlL]?"
     - 	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*"),
     - PATTERNS("csharp",
     - 	 /* Keywords */
     +@@ t/t4034/cpp/pre: str.e+65
     + a*b c/d e%f
     + a+b c-d
     + a<<b c>>d
     +-a<b c<=d e>f g>=h
     ++a<b c<=d e>f g>=h i<=j
     + a==b c!=d
     + a^b c|d e&&f
     + a||b
 -:  ----------- > 5:  037c743d9e3 userdiff-cpp: permit the digit-separating single-quote in numbers
 5:  43a701f5ffd ! 6:  cc9dc967f10 userdiff-cpp: learn the C++ spaceship operator
     @@ Commit message
          Signed-off-by: Johannes Sixt <[email-masked]>
      
       ## t/t4034/cpp/expect ##
     -@@
     - <BOLD>diff --git a/pre b/post<RESET>
     --<BOLD>index 60f3640..f6fbf7b 100644<RESET>
     -+<BOLD>index 144cd98..244f79c 100644<RESET>
     - <BOLD>--- a/pre<RESET>
     - <BOLD>+++ b/post<RESET>
     - <CYAN>@@ -1,30 +1,30 @@<RESET>
      @@ t/t4034/cpp/expect: str.e+<RED>65<RESET><GREEN>75<RESET>
       a<RED>*<RESET><GREEN>*=<RESET>b c<RED>/<RESET><GREEN>/=<RESET>d e<RED>%<RESET><GREEN>%=<RESET>f
       a<RED>+<RESET><GREEN>++<RESET>b c<RED>-<RESET><GREEN>--<RESET>d
       a<RED><<<RESET><GREEN><<=<RESET>b c<RED>>><RESET><GREEN>>>=<RESET>d
     --a<RED><<RESET><GREEN><=<RESET>b c<RED><=<RESET><GREEN><<RESET>d e<RED>><RESET><GREEN>>=<RESET>f g<RED>>=<RESET><GREEN>><RESET>h
     +-a<RED><<RESET><GREEN><=<RESET>b c<RED><=<RESET><GREEN><<RESET>d e<RED>><RESET><GREEN>>=<RESET>f g<RED>>=<RESET><GREEN>><RESET>h i<=<GREEN>><RESET>j
      +a<RED><<RESET><GREEN><=<RESET>b c<RED><=<RESET><GREEN><<RESET>d e<RED>><RESET><GREEN>>=<RESET>f g<RED>>=<RESET><GREEN>><RESET>h i<RED><=<RESET><GREEN><=><RESET>j
       a<RED>==<RESET><GREEN>!=<RESET>b c<RED>!=<RESET><GREEN>=<RESET>d
       a<RED>^<RESET><GREEN>^=<RESET>b c<RED>|<RESET><GREEN>|=<RESET>d e<RED>&&<RESET><GREEN>&=<RESET>f
       a<RED>||<RESET><GREEN>|<RESET>b
      
     - ## t/t4034/cpp/post ##
     -@@ t/t4034/cpp/post: str.e+75
     - a*=b c/=d e%=f
     - a++b c--d
     - a<<=b c>>=d
     --a<=b c<d e>=f g>h
     -+a<=b c<d e>=f g>h i<=>j
     - a!=b c=d
     - a^=b c|=d e&=f
     - a|b
     -
     - ## t/t4034/cpp/pre ##
     -@@ t/t4034/cpp/pre: str.e+65
     - a*b c/d e%f
     - a+b c-d
     - a<<b c>>d
     --a<b c<=d e>f g>=h
     -+a<b c<=d e>f g>=h i<=j
     - a==b c!=d
     - a^b c|d e&&f
     - a||b
     -
       ## userdiff.c ##
      @@ userdiff.c: PATTERNS("cpp",
       	 "|0[xXbB][0-9a-fA-F']+[lLuU]*"
       	 /* floatingpoint numbers that begin with a decimal point */
     - 	 "|\\.[0-9']+([Ee][-+]?[0-9]+)?[fFlL]?"
     + 	 "|\\.[0-9][0-9']*([Ee][-+]?[0-9]+)?[fFlL]?"
      -	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*"),
      +	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*|<=>"),
       PATTERNS("csharp",

-- 
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