//
/// <summary>
/// Creates an expression from a string.
/// </summary>
/// <param name="str">The string.</param>
/// <param name="flags">Flags about parsin.</param>
/// <param name="referenceTable">The table to use for pulling references in, after ones in the file.</param>
/// <returns>The created expression, or null if none.</returns>
//
public static Expression CreateFromStringWithExternalReferenceTable(string str, ParseFlags flags, ReferenceTable referenceTable)
{
var expr = CreateInvalid();
var parserState = new Internal.ParserState();
parserState.ExternalReferenceMap = referenceTable;
// we assume its UTF8 safe since csharp should take care of this
// now start parsing
var rest = expr.p_parseFromString(
str, flags, parserState
);
var postRest = s_trimFrontOfString(rest, parserState);
if (postRest.Length != 0)
{
throw new ExtraDataAfterParsingRootException(parserState.Line, parserState.Column, "Extra data after parsing the root expression");
}
if (expr.ExpressionType == ExpressionType.Invalid)
{
throw new EmptyStringException(parserState.Line, parserState.Column, "No expression found [remained invalid]");
}
return(expr);
}
// returns the part of the string remaining
// will load into self, setting up everything. Assumes we're mpty/null to start.
private string p_parseFromString(string str, ParseFlags parseFlags, Internal.ParserState parserState)
{
if (str.Length == 0)
{
throw new EmptyStringException(parserState.Line, parserState.Column, "Was told to parse an empty string");
}
str = s_trimFrontOfString(str, parserState);
if (str.Length == 0)
{
return("");
}
// start parsing types:
// if first two characters are #(, we're an array.
// if @( we're a map.
// if [] we're a ref.
// if < we're a binary string
// otherwise, we're a value.
if (str.Length >= 2 && str.Substring(0, 2) == "#(")
{
// We're an array
m_type = ExpressionType.Array;
m_array.Init();
// move our string forward
str = str.Substring(2);
parserState.Column += 2;
// continue building children as needed
while (true)
{
str = s_trimFrontOfString(str, parserState);
if (str.Length == 0)
{
throw new ArrayMissingEndParenException(parserState.Line, parserState.Column, "An Array was missing its ending paren");
}
if (str.Substring(0, 1) == ")") // end array
{
break; // done
}
else
{
// parse as a new expression
var newExpression = CreateNull();
str = newExpression.p_parseFromString(str, parseFlags, parserState);
// add it to our array
ArrayAddElementToEnd(newExpression);
}
}
str = str.Substring(1); // remove the end array
parserState.Column += 1;
// done with array
return(str);
}
else if (str.Length >= 2 && str.Substring(0, 2) == "@(")
{
// We're a map
m_type = ExpressionType.Map;
m_map.Init();
// move our string accordingly
str = str.Substring(2);
parserState.Column += 2;
// build our children as needed
while (true)
{
str = s_trimFrontOfString(str, parserState);
if (str.Length == 0)
{
throw new MapMissingEndParenException(parserState.Line, parserState.Column, "A Map was missing its ending paren");
}
if (str.Length >= 1 && str.Substring(0, 1) == ")") // end map
{
break;
}
else
{
// parse as a new expression - we'll alternate keys and values
// keep our previous position just in case the value is bad.
int prevLine = parserState.Line;
int prevColumn = parserState.Column;
var keyExpression = CreateNull();
str = keyExpression.p_parseFromString(str, parseFlags, parserState);
if (keyExpression.ExpressionType != ExpressionType.Value)
{
throw new MapKeyMustBeAValueException(prevLine, prevColumn, "Map keys must be a value");
}
var valueExpression = CreateInvalid();
try
{
str = valueExpression.p_parseFromString(str, parseFlags, parserState);
}
catch (EmptyStringException)
{
// we ignore ESEs because we want to consider that no value for a better error.
// if not, the exception is good.
}
if (valueExpression.ExpressionType == ExpressionType.Invalid)
{
throw new MapNoValueException(prevLine, prevColumn, "Map key must have a value");
}
// ok now we have the key and the value
// both malloc so we can free later
MapSetValueForKey(keyExpression.Value, valueExpression);
}
}
// remove the end map
str = str.Substring(1);
parserState.Column += 1;
// done with map
return(str);
}
else if (str.Length >= 1 && str.Substring(0, 1) == "[")
{
// the current expression being processed is the one the attribute will be linked to.
// process till the closing ]
var endingBracketIndex = str.IndexOf(']');
if (endingBracketIndex == -1)
{
throw new ReferenceMissingEndBracketException(parserState.Line, parserState.Column, "A reference [] is missing its ending bracket");
}
var refName = str.Substring(1, endingBracketIndex - 1);
// validate the contents
var invalidName = false;
for (int i = 0; i < refName.Length; ++i)
{
char v = refName[i];
bool isAlpha = (v >= 'a' && v <= 'z') || (v >= 'A' && v <= 'Z');
bool isNumber = (v >= '0' && v <= '9');
bool isUnder = (v == '_');
if (i == 0 && (isAlpha || isUnder))
{
}
else if (i != 0 && (isAlpha || isNumber || isUnder))
{
}
else
{
invalidName = true;
break;
}
}
if (invalidName)
{
throw new ReferenceInvalidNameException(parserState.Line, parserState.Column, "A reference doesn't have a valid name");
}
// move forward
parserState.MoveForwardBasedOnString(str.Substring(0, endingBracketIndex + 1));
str = str.Substring(endingBracketIndex + 1);
// continue parsing at the same level : stored the reference name
var resultString = p_parseFromString(str, parseFlags, parserState);
// now bind the ref - creating a copy of what was made. This will be used for the template.
parserState.InternalReferenceMap.SetExpressionForKey(refName, Copy());
// and continue
return(resultString);
}
else if (str.Length >= 2 && str.Substring(0, 2) == "*[")
{
// parse the reference name
var endingBracketIndex = str.IndexOf(']');
if (endingBracketIndex == -1)
{
throw new ReferenceInsertMissingEndBracketException(parserState.Line, parserState.Column, "A reference insert *[] is missing its ending bracket");
}
var refName = str.Substring(2, endingBracketIndex - 2);
// move forward
parserState.MoveForwardBasedOnString(str.Substring(0, endingBracketIndex + 1));
str = str.Substring(endingBracketIndex + 1);
var referenceExpr = parserState.InternalReferenceMap.ExpressionForKey(refName);
if (referenceExpr == null)
{
// try again with the external if we have it
if (parserState.ExternalReferenceMap != null)
{
referenceExpr = parserState.ExternalReferenceMap.ExpressionForKey(refName);
}
}
if (referenceExpr == null)
{
// not found
throw new ReferenceUnknownReferenceException(parserState.Line, parserState.Column, "Tried to insert a reference, but couldn't find it.");
}
// copy this into ourself
p_copyFrom(referenceExpr);
return(str);
}
// null expressions will be treated as a value, and then parsed seperately.
else if (
str.Length >= 1 && str.Substring(0, 1) == "<"
)
{
// look for the ending <
var endingQuote = str.IndexOf('>');
if (endingQuote == -1)
{
// not found
throw new BinaryDataNoEndingException(parserState.Line, parserState.Column, "Tried to find the ending > for binary data, but not found.");
}
byte[] data;
try
{
data = System.Convert.FromBase64String(str.Substring(1, endingQuote - 1)); // -1 for starting quote. ending was not part.
}
catch (Exception)
{
throw new BinaryDataInvalidBase64Exception(parserState.Line, parserState.Column, "Unable to decode the base64 data.");
}
m_type = ExpressionType.BinaryData;
m_binaryData.data = data;
parserState.MoveForwardBasedOnString(str.Substring(0, endingQuote + 1));
return(str.Substring(endingQuote + 1));
}
else if (str.Length >= 1) // its a value: must be at least one character
{
var val = s_createValueOfString(str, parserState);
// was it a null/nil string?
if (val.value == "nil" || val.value == "null")
{
m_type = ExpressionType.Null;
}
else
{
m_type = ExpressionType.Value;
m_value.data = val.value;
}
parserState.MoveForwardBasedOnString(str.Substring(0, val.endIndex));
return(str.Substring(val.endIndex));
}
// otherwise we have no idea what happened
return("");
}
private static PrivateWexprStringValue s_createValueOfString(string str, Internal.ParserState parserState)
{
// two pass:
// first pass, get the length of the size
// second pass, store the buffer
int bufferLength = 0;
bool isQuotedString = false;
bool isEscaped = false;
int pos = 0; // position we're parsing at
if (str[0] == '"')
{
isQuotedString = true;
++pos;
}
while (pos < str.Length)
{
char c = str[pos];
if (isQuotedString)
{
if (isEscaped)
{
// we're in an escape. Is it valid?
if (s_isEscapeValid(c))
{
++bufferLength; // counts
isEscaped = false; // escape ended
}
else
{
throw new InvalidStringEscapeException(parserState.Line, parserState.Column, "Invalid escape found in teh string");
}
}
else
{
if (c == '"')
{
// end quote - part of us
++pos;
break;
}
else if (c == '\\')
{
// we're escaping
isEscaped = true;
}
else
{
// otherwise it's a character
++bufferLength;
}
}
}
else
{
// have we neded the word?
if (s_isNotBarewordSafe(c))
{
// ended - not part of us
break;
}
// otherwise, it's a character
++bufferLength;
}
++pos;
}
if (bufferLength == 0 && !isQuotedString) // cannot have an empty barewords string
{
throw new EmptyStringException(parserState.Line, parserState.Column, "Was told to parse an empty string");
}
int end = pos;
// we now know our buffer size and the string has been checked
string buffer = "";
int writePos = 0;
pos = 0;
if (isQuotedString)
{
pos = 1;
}
while (writePos < bufferLength)
{
char c = str[pos];
if (isQuotedString)
{
if (isEscaped)
{
char escapedValue = s_valueForEscape(c);
buffer += escapedValue;
++writePos;
isEscaped = false;
}
else
{
if (c == '\\')
{
// we're escaping
isEscaped = true;
}
else
{
// otherwise it's a character
buffer += c;
++writePos;
}
}
}
else
{
// its a character
buffer += c;
++writePos;
}
// next character
++pos;
}
var ret = new PrivateWexprStringValue();
ret.value = buffer;
ret.endIndex = end;
return(ret);
}
// Trims the given string by removing whitespace or comments from the beginning of the string
private static string s_trimFrontOfString(string str, Internal.ParserState parserState)
{
while (true)
{
if (str.Length == 0) // trimmed everything
{
return(str);
}
char first = str[0];
// skip whitespace
if (s_isWhitespace(first))
{
str = str.Substring(1);
if (s_isNewline(first))
{
parserState.Line += 1;
parserState.Column = 1;
}
else
{
parserState.Column += 1;
}
}
// comment
else if (first == ';')
{
bool isTillNewline = true;
if (str.Length >= 4)
{
if (str.Substring(0, 4) == s_StartBlockComment)
{
isTillNewline = false;
}
}
int endIndex =
(isTillNewline
? str.IndexOf('\n') // end of line
: str.IndexOf(s_EndBlockComment)
);
int lengthToSkip = isTillNewline ? 1 : s_EndBlockComment.Length;
// Move forward columns/rows as needed
parserState.MoveForwardBasedOnString(
str.Substring(0, (endIndex == -1) ? str.Length : (endIndex + lengthToSkip))
);
if (endIndex == -1 ||
endIndex > str.Length - lengthToSkip)
{
str = ""; // dead
}
else // slice
{
str = str.Substring(endIndex + lengthToSkip); // skip the comment
}
}
else
{
break;
}
}
return(str);
}
