Stream parsing operators

A range of operators used for stream parsing of textual/numerical data—most usually a note's $Text):

Such operators are:

• fail()
• JSON.each([pathStr]){actions}
• JSON.json[itemNum]
• JSON.json[keyStr]
• JSON.jsonValue()
• JSON.jsonValue(pathStr)
• String.captureJson()
• String.captureLine([targetAttributeStr])
• String.captureNumber([targetAttributeStr])
• String.captureRest([targetAttributeStr])
• String.captureTo(matchStr[, targetAttributeStr])
• String.captureToken([targetAttributeStr])
• String.captureWord([targetAttributeStr])
• String.captureXML()
• String.eachLine(loopVar[:condition]){actions}
• String.expect(matchStr)
• String.expectNumber()
• String.expectWhitespace()
• String.expectWord()
• String.failed()
• String.skip(charsNum)
• String.skipLine()
• String.skipTo(matchStr)
• String.skipToNumber()
• String.skipWhitespace()
• String.try{actions}[.thenTry{actions}]
• XML.each(pathStr){action}
• XML.xml(pathStr)