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Function `std.algorithm.searching.balancedParens`

Checks whether r has "balanced parentheses", i.e. all instances of lPar are closed by corresponding instances of rPar. The parameter maxNestingLevel controls the nesting level allowed. The most common uses are the default or 0. In the latter case, no nesting is allowed.


						
				bool balancedParens(Range, E)(
				
  Range r,
				
  E lPar,
				
  E rPar,
				

				  size_t maxNestingLevel = size_t.max
				

				)
				

				if (isInputRange!Range && is(typeof(r.front == lPar)));

Parameters

Name	Description
r	The range to check.
lPar	The element corresponding with a left (opening) parenthesis.
rPar	The element corresponding with a right (closing) parenthesis.
maxNestingLevel	The maximum allowed nesting level.

Returns

true if the given range has balanced parenthesis within the given maximum nesting level; false otherwise.

Example

auto s = "1 + (2 * (3 + 1 / 2)";
assert(!balancedParens(s, '(', ')'));
s = "1 + (2 * (3 + 1) / 2)";
assert(balancedParens(s, '(', ')'));
s = "1 + (2 * (3 + 1) / 2)";
assert(!balancedParens(s, '(', ')', 0));
s = "1 + (2 * 3 + 1) / (2 - 5)";
assert(balancedParens(s, '(', ')', 0));
s = "f(x) = ⌈x⌉";
assert(balancedParens(s, '⌈', '⌉'));

Authors

Andrei Alexandrescu

License

Boost License 1.0.