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Implement XPath abbreviate of parentheses and fix some bugs #328

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Implement XPath abbreviate of parentheses and fix some bugs #328

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31 changes: 24 additions & 7 deletions lib/rexml/parsers/xpathparser.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -103,14 +103,16 @@ def abbreviate(path_or_parsed)
component << ']'
when :document
components << ""
when :function
component << parsed.shift
component << "( "
component << predicate_to_path(parsed.shift[0]) {|x| abbreviate(x)}
component << " )"
when :literal
component << quote_literal(parsed.shift)
when :function, :literal, :group, :neg, :and, :or, :mult, :plus, :minus, :neq, :eq, :lt, :gt, :lteq, :gteq, :div, :mod, :union
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@tompng tompng Jun 6, 2026

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This is not good, but we need to do this to avoid infinite recursion of unknown operator.
predicate_to_path calls abbreviate if predicate_to_path doesn't know the operator.

Some possible workaround for this may break XPathParser#expand which is not tested and the spec is unknown.

component = ''
components << component
parsed.unshift(op)
component << predicate_to_path(parsed) {|x| abbreviate(x)}
Comment on lines +106 to +110
else
unless component
component = ''
components << component
end
component << "UNKNOWN("
component << op.inspect
component << ")"
Expand Down Expand Up @@ -188,6 +190,12 @@ def predicate_to_path(parsed, &block)
op = "!="
when :union
op = "|"
when :plus
op = "+"
when :minus
op = "-"
when :mult
op = "*"
end
left = predicate_to_path( parsed.shift, &block )
right = predicate_to_path( parsed.shift, &block )
Expand All @@ -196,6 +204,10 @@ def predicate_to_path(parsed, &block)
path << op.to_s
path << " "
path << right
when :neg
parsed.shift
path << "-"
path << predicate_to_path( parsed, &block )
Comment on lines +207 to +210
when :function
parsed.shift
name = parsed.shift
Expand All @@ -209,6 +221,11 @@ def predicate_to_path(parsed, &block)
when :literal
parsed.shift
path << quote_literal(parsed.shift)
when :group
parsed.shift
path << "("
path << yield(parsed.shift)
path << ")"
else
path << yield( parsed )
end
Expand Down
50 changes: 50 additions & 0 deletions test/parser/test_xpath.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,56 @@ def test_document
abbreviate("/"))
end

def test_raw_literal
assert_equal("1",
abbreviate("1"))
end

def test_unary_operator
assert_equal("-1",
abbreviate("-1"))
assert_equal("/a[-/b]",
abbreviate("/a[-/b]"))
end

def test_binary_operator
assert_equal("1 * 2 + 3 - 4",
abbreviate("1 * 2 + 3 - 4"))
assert_equal("/a | /b",
abbreviate("/a | /b"))
assert_equal("/a[1 + /b * 2]",
abbreviate("/a[1 + /b * 2]"))
end

def test_operand_with_path
assert_equal("/a/b + 1",
abbreviate("/a/b + 1"))
end

def test_paren
assert_equal("(1 + 2) * 3",
abbreviate("(1 + 2) * 3"))
end

def test_predicate_paren
assert_equal("/a[(b + c) * d]",
abbreviate("/a[(b + c) * d]"))
end

def test_path_paren
assert_equal("(a/b)[2]",
abbreviate("(a/b)[2]"))
end

def test_unknown_not_infinitely_recursing
assert_instance_of(String, abbreviate([:unknown]))
end

def test_function
assert_equal("string-length(a/b[last()])",
abbreviate("string-length(a/b[last()])"))
end

def test_descendant_or_self_only
assert_equal("//",
abbreviate("/descendant-or-self::node()/"))
Expand Down
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