10.2.13 Statement Block Symbols

There are a few occasions where a statement block might be used inside an expression. One is in C or C++ code using the gcc extension for this, e.g:

 1: int res = ({
 2:         int y = foo (); int z;
 3:         if (y > 0) z = y; else z = - y;
 4:         z;
 5:     });

Lines 2 and 5 get the inexpr-statement syntax, besides the symbols they’d get in a normal block. Therefore, the indentation put on inexpr-statement is added to the normal statement block indentation. An inexpr-statement syntactic element doesn’t contain an anchor position.

C++11’s lambda expressions involve a block inside a statement. For example:

 1:  std::for_each(someList.begin(), someList.end(), [&total](int x) {
 2:                                                     total += x;
 3:                                                 });

Here a lambda expressions begins at the open bracket on line 1 and ends at the closing brace on line 3. Line 2, in addition to the familiar defun-block-intro syntactic element, is also prefixed by an inlambda element, which is typically used to indent the entire lambda expression to under the opening bracket.

In Pike code, there are a few other situations where blocks occur inside statements, as illustrated here:

 1: array itgob()
 2: {
 3:     string s = map (backtrace()[-2][3..],
 4:                     lambda
 5:                         (mixed arg)
 6:                     {
 7:                         return sprintf ("%t", arg);
 8:                     }) * ", " + "\n";
 9:     return catch {
10:             write (s + "\n");
11:         };
12: }

Lines 4 through 8 contain a lambda function, which CC Mode recognizes by the lambda keyword. If the function argument list is put on a line of its own, as in line 5, it gets the lambda-intro-cont syntax. The function body is handled as an inline method body, with the addition of the inlambda syntactic symbol. This means that line 6 gets inlambda and inline-open, and line 8 gets inline-close⁴².

On line 9, catch is a special function taking a statement block as its argument. The block is handled as an in-expression statement with the inexpr-statement syntax, just like the gcc extended C example above. The other similar special function, gauge, is handled like this too.