More json sketching.
This commit is contained in:
Jesse Brault
parent
053d08849e
commit
803b95c5dc
@ -1,21 +1,21 @@
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ns jsonexample
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fn main()
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let rawJson: String = match io::readFile("myDoc.json")
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Success(s) => s,
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Failure(err) => exit(err)
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end
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let o: obj = match parseJsonObj(rawJson)
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let o: obj = match parseJsonObj('{ "a": { "b": { "c": [42] }} }')
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Success(o) => o,
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Failure(err) => exit(err)
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Failure(err) => panic!("There was an error during Json parsing: ${err}")
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end
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assertEq!(o.a.b.c[0], 42)
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end
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fn parseJsonObj(s: String) -> obj
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fn parseJsonObj(s: String) -> Result<obj, JsonParseError>
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let lexer = JsonLexer(s)
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let parser = JsonParser(lexer)
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parser.object()
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try
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parser.object()
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catch (parseError: JsonParseError)
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Failure(parseError)
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end
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end
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enum JsonToken
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@ -29,20 +29,58 @@ enum JsonToken
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Boolean(Boolean)
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end
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class String
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pub fn <R> matchAt(startIndex: Int, matchers: Map<Regex, R | fn (match: String) -> R), opts: obj {
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ignoreWhitespace: boolean,
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endIndex: Int
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}) -> Option<R>
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todo!()
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platform class String
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pub fn <R> matchAt(startIndex: Int, matchers: Map<Regex, R | fn (match: String) -> R), opts: obj + { ignoreWhitespace: Boolean }) -> Option<R>
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let slice: String = if opts.ignoreWhitespace then
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/[\t\n\r ]*(<rest>.*)/.match(self[startIndex..]).rest as String
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else
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self[startIndex..]
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end
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for [regex, result] in matchers do
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if regex.test(slice) is Some(match) then
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if result is Fn then
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Some(result(match))
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else
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Some(result)
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end
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end
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end
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None
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end
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end
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platform class Regex
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int RegexMatchBase
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val match: String
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val groups: [String],
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val namedGroups: Map<String, String>
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end
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pub int RegexMatch
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props!::<RegexMatchBase>()
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end
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platform fn doMatch(s) -> Option<RegexMatchBase>
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pub fn match(s: String) -> Option<obj : RegexMatch>
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doMatch(s).map { base ->
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dyn obj {
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...base,
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propertyMissing: { name: String ->
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base.namedGroups.get(name).unwrap()
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}
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}
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}
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end
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end
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class JsonLexer(val source: String)
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var index: Int
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pub fn nextToken() -> Option<JsonToken>
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let token: Option<JsonToken> = source.matchAt(index, [
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fn matchCurrent() -> Option<JsonToken>
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source.matchAt(index, [
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/\{/ => JsonToken::LBrace,
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/}/ => JsonToken::RBrace,
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/\[/ => JsonToken::LSquare,
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@ -52,26 +90,49 @@ class JsonLexer(val source: String)
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/false/ => JsonToken::False(false),
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// The following is not a good way for matching strings but whatever
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/"%w*"/ => { stringWithQuotes => JsonToken::String(stringWithQuotes[1..-1]) }
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], ignoreWhitespace: true)
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match token?
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JsonToken::LBrace | JsonToken::RBrace | JsonToken::LSquare | JsonToken::RSquare | JsonToken::Comma => do index++ end
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JsonToken::String(s) => index += s.len() + 2,
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JsonToken::Number(n) => index += n.toString().len(),
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JsonToken::Boolean(b) => match b
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true => do index += 4 end
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false => do index += 5 end
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end
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end
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token
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], obj { ignoreWhitespace: true })
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end
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pub fn nextToken() -> Option<JsonToken>
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matchCurrent().ifSome { token ->
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match token
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JsonToken::LBrace | JsonToken::RBrace | JsonToken::LSquare | JsonToken::RSquare | JsonToken::Comma => index++,
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JsonToken::String(s) => index += s.len() + 2,
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JsonToken::Number(n) => index += n.toString().len(),
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JsonToken::Boolean(b) => match b
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true => index += 4,
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false => index += 5,
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end
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end
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}
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end
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pub fn peek() -> Option<JsonToken> alias matchCurrent
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end
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class JsonParser(val lexer: JsonLexer)
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macro parseError!($message)
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throw JsonParserError($message)
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end
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macro expect!($tokenType)
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match lexer.nextToken()
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Some(JsonToken::$tokenType) => do end,
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_ => panic! "Expected ${$tokenType}"
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Some(token) => match token
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JsonToken::$tokenType => do end,
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_ => parseError!("Expected ${$tokenType}")
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end,
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_ => parseError!("Expected ${$tokenType}")
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end
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end
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macro peek!($tokenType)
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match lexer.peek()
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Some(token) => match token
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JsonToken::$tokenType => true,
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_ => false
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end,
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None => false
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end
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end
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@ -86,29 +147,65 @@ class JsonParser(val lexer: JsonLexer)
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end
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fn keyValue() -> Option<(String, Any)>
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let key = match lexer.nextToken()
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Some(JsonToken::String(s)) => s,
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_ => return None
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let key = match lexer.peek()
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Some(token) => do
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match token
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JsonToken::String(s) => s,
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_ => parseError!("Expected String")
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end
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end,
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_ => do return None end
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end
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let value = value()
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Some((key, value))
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end
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fn value() -> Any
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match lexer.nextToken()
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match lexer.peek()
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Some(token) => match token
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JsonToken::String(s) => s,
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JsonToken::Number(n) => n,
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JsonToken::Boolean(b) => b,
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JsonToken::LBrace => object(),
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JsonToken::LSquare => array()
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JsonToken::LSquare => array(),
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_ => do
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match lexer.nextToken()
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JsonToken::String(s) => s,
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JsonToken::Number(n) => n,
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JsonToken::Boolean(b) => b,
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_ => parseError!("Expected String, Number, or Boolean")
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end
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end
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end,
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None => panic! "Expected LBrace, LSquare, String, Number, or Boolean"
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None => parseError!("Expected LBrace, LSquare, String, Number, or Boolean")
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end
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end
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fn array() -> Array<Any>
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todo!()
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fn array() -> [Any]
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expect!(LSquare)
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let results: List<Any> = []
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while true do
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match lexer.peek()
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Some(token) => match token
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JsonToken::LBrace => results << object(),
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JsonToken::LSquare => results << array(),
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_ => do
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match lexer.nextToken()
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JsonToken::String(s) => results << s,
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JsonToken::Number(n) => results << n,
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JsonToken::Boolean(b) => results << b,
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_ => parseError!("Expected String, Number, or Boolean")
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end
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end
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end,
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None => panic! "Expected LBrace, LSquare, String, Number, or Boolean"
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end
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match lexer.nextToken()
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Some(token) => match token
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JsonToken::Comma => continue,
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JsonToken::RSquare => break
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end
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_ => panic! "Expected Comma or RSquare"
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end
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end
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expect!(RSquare)
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end
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end
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