// This switch follows more or less a DEA to this EBNF
// COMMAND-EBNF := COMMAND
// COMMAND := (!ARGUMENT \s+ (ARGUMENT|\s)*)
// ARGUMENT := COMMAND|FREESTRING|QUOTESTRING
// FREESTRING := [^)]+
// QUOTESTRING := "[<anything but ", \" is ok>]+"
public static AstNode ParseCommandRequest(string request, char commandChar = DefaultCommandChar, char delimeterChar = DefaultDelimeterChar)
{
AstCommand root = null;
var comAst = new Stack <AstCommand>();
var build = BuildStatus.ParseCommand;
var strb = new StringBuilder();
var strPtr = new StringPtr(request);
while (!strPtr.End)
{
AstCommand buildCom;
switch (build)
{
case BuildStatus.ParseCommand:
// Got a command
buildCom = new AstCommand();
// Consume CommandChar if left over
if (strPtr.Char == commandChar)
{
strPtr.Next(commandChar);
}
if (root == null)
{
root = buildCom;
}
else
{
comAst.Peek().Parameter.Add(buildCom);
}
comAst.Push(buildCom);
build = BuildStatus.SelectParam;
break;
case BuildStatus.SelectParam:
strPtr.SkipChar(delimeterChar);
if (strPtr.End)
{
build = BuildStatus.End;
}
else
{
switch (strPtr.Char)
{
case '"':
build = BuildStatus.ParseQuotedString;
//goto case BuildStatus.ParseQuotedString;
break;
case '(':
if (!strPtr.HasNext)
{
build = BuildStatus.ParseFreeString;
}
else if (strPtr.IsNext(commandChar))
{
strPtr.Next('(');
build = BuildStatus.ParseCommand;
}
else
{
build = BuildStatus.ParseFreeString;
}
break;
case ')':
if (comAst.Count <= 0)
{
build = BuildStatus.End;
}
else
{
comAst.Pop();
if (comAst.Count <= 0)
{
build = BuildStatus.End;
}
}
strPtr.Next();
break;
default:
build = BuildStatus.ParseFreeString;
break;
}
}
break;
case BuildStatus.ParseFreeString:
strb.Clear();
var valFreeAst = new AstValue();
using (strPtr.TrackNode(valFreeAst))
{
for (; !strPtr.End; strPtr.Next())
{
if ((strPtr.Char == '(' && strPtr.HasNext && strPtr.IsNext(commandChar)) ||
strPtr.Char == ')' ||
strPtr.Char == delimeterChar)
{
break;
}
strb.Append(strPtr.Char);
}
}
valFreeAst.Value = strb.ToString();
buildCom = comAst.Peek();
buildCom.Parameter.Add(valFreeAst);
build = BuildStatus.SelectParam;
break;
case BuildStatus.ParseQuotedString:
strb.Clear();
strPtr.Next('"');
var valQuoAst = new AstValue();
using (strPtr.TrackNode(valQuoAst))
{
bool escaped = false;
for (; !strPtr.End; strPtr.Next())
{
if (strPtr.Char == '\\')
{
escaped = true;
}
else if (strPtr.Char == '"')
{
if (escaped)
{
strb.Length--;
}
else
{
strPtr.Next(); break;
}
escaped = false;
}
else
{
escaped = false;
}
strb.Append(strPtr.Char);
}
}
valQuoAst.Value = strb.ToString();
buildCom = comAst.Peek();
buildCom.Parameter.Add(valQuoAst);
build = BuildStatus.SelectParam;
break;
case BuildStatus.End:
strPtr.JumpToEnd();
break;
default: throw new InvalidOperationException();
}
}
return(root);
}
// This switch follows more or less a DEA to this EBNF
// COMMAND-EBNF := <COMMAND> | $.*^
// COMMAND := '!' <ARGUMENT> (\s+ <ARGUMENT>)*
// ARGUMENT := '(' <COMMAND> ')'? | <FREESTRING> | <QUOTESTRING>
// FREESTRING := [^)]+
// QUOTESTRING := '"' [<anything but ", \" is ok>]* '"'
public static AstNode ParseCommandRequest(string request, char commandChar = DefaultCommandChar, char delimeterChar = DefaultDelimeterChar)
{
AstCommand?root = null;
var comAst = new Stack <AstCommand>();
var build = BuildStatus.ParseCommand;
var strb = new StringBuilder();
var strPtr = new StringPtr(request);
var startTrim = request.AsSpan().TrimStart();
if (startTrim.IsEmpty || startTrim[0] != commandChar)
{
return(new AstValue(request, StringType.FreeString)
{
Length = request.Length,
Position = 0,
Value = request,
});
}
while (!strPtr.End)
{
AstCommand buildCom;
switch (build)
{
case BuildStatus.ParseCommand:
// Got a command
buildCom = new AstCommand(request);
// Consume CommandChar if left over
if (strPtr.Char == commandChar)
{
strPtr.Next(commandChar);
}
if (root is null)
{
root = buildCom;
}
else
{
comAst.Peek().Parameter.Add(buildCom);
}
comAst.Push(buildCom);
build = BuildStatus.SelectParam;
break;
case BuildStatus.SelectParam:
strPtr.SkipChar(delimeterChar);
if (strPtr.End)
{
build = BuildStatus.End;
}
else
{
switch (strPtr.Char)
{
case '"':
case '\'':
build = BuildStatus.ParseQuotedString;
//goto case BuildStatus.ParseQuotedString;
break;
case '(':
if (!strPtr.HasNext)
{
build = BuildStatus.ParseFreeString;
}
else if (strPtr.IsNext(commandChar))
{
strPtr.Next('(');
build = BuildStatus.ParseCommand;
}
else
{
build = BuildStatus.ParseFreeString;
}
break;
case ')':
if (comAst.Count <= 0)
{
build = BuildStatus.End;
}
else
{
buildCom = comAst.Pop();
foreach (var param in buildCom.Parameter)
{
if (param is AstValue astVal)
{
astVal.TailLength = strPtr.Index - param.Position;
}
}
if (comAst.Count <= 0)
{
build = BuildStatus.End;
}
}
strPtr.Next();
break;
default:
build = BuildStatus.ParseFreeString;
break;
}
}
break;
case BuildStatus.ParseFreeString:
var valFreeAst = new AstValue(request, StringType.FreeString);
using (strPtr.TrackNode(valFreeAst))
{
for (; !strPtr.End; strPtr.Next())
{
if ((strPtr.Char == '(' && strPtr.HasNext && strPtr.IsNext(commandChar)) ||
strPtr.Char == ')' ||
strPtr.Char == delimeterChar)
{
break;
}
}
}
buildCom = comAst.Peek();
buildCom.Parameter.Add(valFreeAst);
build = BuildStatus.SelectParam;
break;
case BuildStatus.ParseQuotedString:
strb.Clear();
char quoteChar;
if (strPtr.TryNext('"'))
{
quoteChar = '"';
}
else if (strPtr.TryNext('\''))
{
quoteChar = '\'';
}
else
{
throw new Exception("Parser error");
}
var valQuoAst = new AstValue(request, StringType.QuotedString);
using (strPtr.TrackNode(valQuoAst))
{
bool escaped = false;
for (; !strPtr.End; strPtr.Next())
{
if (strPtr.Char == '\\')
{
escaped = true;
}
else if (strPtr.Char == quoteChar)
{
if (!escaped)
{
strPtr.Next();
break;
}
else
{
strb.Length--;
escaped = false;
}
}
else
{
escaped = false;
}
strb.Append(strPtr.Char);
}
}
valQuoAst.Value = strb.ToString();
buildCom = comAst.Peek();
buildCom.Parameter.Add(valQuoAst);
build = BuildStatus.SelectParam;
break;
case BuildStatus.End:
strPtr.JumpToEnd();
break;
default: throw new InvalidOperationException();
}
}
return(root ?? throw new InvalidOperationException("No ast was built"));
}
