/*
Construct a Regex from a given string
1. First examine the given string.
If it is empty, there is nothing to do, so return (having cleared m_sub as a precaution).
2. Look to see if the string begins with a bracket ( . If so, find the matching ) .
This is not as simple as it might be because )s inside quotes or [] or escaped will not count.
Recursively call the constructor for the regular expression between the () s.
Mark everything up to the ) as used, and go to step 9.
3. Look to see if the string begins with a bracket [ . If so, find the matching ] , watching for escapes.
Construct a ReRange for everything between the []s.
Mark everything up to the ] as used, and go to step 9.
4. Look to see if the string begins with a ' or " . If so, build the contents interpreting
escaped special characters correctly, until the matching quote is reached.
Construct a ReStr for the contents, mark everything up to the final quote as used, and go to step 9.
4a. Look to see if the string begins with a U' or U" . If so, build the contents interpreting
escaped special characters correctly, until the matching quote is reached.
Construct a ReUStr for the contents, mark everything up to the final quote as used, and go to step 9.
5. Look to see if the string begins with a \ .
If so, build a ReStr for the next character (special action for ntr),
mark it as used, and go to step 9.
6. Look to see if the string begins with a { .
If so, find the matching }, lookup the symbolic name in the definitions table,
recursively call this constructor on the contents,
mark everything up to the } as used, and go to step 9.
7. Look to see if the string begins with a dot.
If so, construct a ReRange("^\n"), mark the . as used, and go to step 9.
8. At this point we conclude that there is a simple character at the start of the regular expression.
Construct a ReStr for it, mark it as used, and go to step 9.
9. If the string is exhausted, return.
We have a simple Regex whose m_sub contains what we can constructed.
10. If the next character is a ? , *, or +, construct a ReOpt, ReStart, or RePlus respectively
out of m_sub, and make m_sub point to this new class instead. Mark the character as used.
11. If the string is exhausted, return.
12. If the next character is a | , build a ReAlt using the m_sub we have and the rest of the string.
13. Otherwise build a ReCat using the m_sub we have and the rest of the string.
*/
public Regex(TokensGen tks,int p,string str)
{
int n = str.Length;
int nlp = 0;
int lbrack = 0;
int quote = 0;
int j;
char ch;
//1. First examine the given string.
// If it is empty, there is nothing to do, so return (having cleared m_sub as a precaution).
m_sub = null;
if (n==0)
return;
//2. Look to see if the string begins with a bracket ( . If so, find the matching ) .
// This is not as simple as it might be because )s inside quotes or [] or escaped will not count.
// Recursively call the constructor for the regular expression between the () s.
// Mark everything up to the ) as used, and go to step 9.
else if (str[0]=='(')
{ // identify a bracketed expression
for (j = 1; j < n; j++)
if (str[j] == '\\')
j++;
else if (str[j] == ']' && lbrack > 0)
lbrack = 0;
else if (lbrack > 0)
continue;
else if (str[j] == '"' || str[j] == '\'')
{
if (quote == str[j])
quote = 0;
else if (quote == 0)
quote = str[j];
}
else if (quote > 0)
continue;
else if (str[j] == '[')
lbrack++;
else if (str[j] == '(')
nlp++;
else if (str[j] == ')' && nlp-- == 0)
break;
if (j==n)
goto bad;
m_sub = new Regex (tks,p+1,str.Substring(1,j-1));
j++;
//3. Look to see if the string begins with a bracket [ . If so, find the matching ] , watching for escapes.
// Construct a ReRange for everything between the []s.
// Mark everything up to the ] as used, and go to step 9.
}
else if (str[0]=='[')
{ // range of characters
for (j=1;j<n && str[j]!=']';j++)
if (str[j]=='\\')
j++;
if (j==n)
goto bad;
m_sub = new ReRange(tks,str.Substring(0,j+1));
j++;
}
//4. Look to see if the string begins with a ' or " . If so, build the contents interpreting
// escaped special characters correctly, until the matching quote is reached.
// Construct a CReStr for the contents, mark everything up to the final quote as used, and go to step 9.
else if (str[0] == '\'' || str[0] == '"')
{ // quoted string needs special treatment
StringBuilder qs = new StringBuilder();
for (j=1;j<n && str[j]!=str[0];j++)
if (str[j]=='\\')
switch (str[++j])
{
case 'n': qs.Append('\n'); break;
case 'r': qs.Append('\r'); break;
case 't': qs.Append('\t'); break;
case 'v': qs.Append('\v'); break;
case '\\': qs.Append('\\'); break;
case '\'': qs.Append('\''); break;
case '0': qs.Append((char) 0); break; // 4.7f
case '"': qs.Append('"'); break;
case '\n': break;
default: qs.Append(str[j]); break;
}
else
qs.Append(str[j]);
if (j==n)
goto bad;
j++;
m_sub = new ReStr(tks,qs.ToString());
}
//4a. Look to see if the string begins with a U' or U" . If so, build the contents interpreting
// escaped special characters correctly, until the matching quote is reached.
// Construct a ReUStr for the contents, mark everything up to the final quote as used, and go to step 9.
else if (str.StartsWith("U\"")||str.StartsWith("U'"))
{ // quoted string needs special treatment
StringBuilder qs = new StringBuilder();
for (j=2;j<n && str[j]!=str[1];j++)
if (str[j]=='\\')
switch (str[++j])
{
case 'n': qs.Append('\n'); break;
case 'r': qs.Append('\r'); break;
case 't': qs.Append('\t'); break;
case 'v': qs.Append('\v'); break;
case '\\': qs.Append('\\'); break;
case '\'': qs.Append('\''); break;
case '"': qs.Append('"'); break;
case '\n': break;
default: qs.Append(str[j]); break;
}
else
qs.Append(str[j]);
if (j==n)
goto bad;
j++;
m_sub = new ReUStr(tks,qs.ToString());
}
//5. Look to see if the string begins with a \ .
// If so, build a ReStr for the next character (special action for ntr),
// mark it as used, and go to step 9.
else if (str[0]=='\\')
{
switch (ch = str[1])
{
case 'n': ch = '\n'; break;
case 't': ch = '\t'; break;
case 'r': ch = '\r'; break;
case 'v': ch = '\v'; break;
}
m_sub = new ReStr(tks,ch);
j = 2;
//6. Look to see if the string begins with a { .
// If so, find the matching }, lookup the symbolic name in the definitions table,
// recursively call this constructor on the contents,
// mark everything up to the } as used, and go to step 9.
}
else if (str[0]=='{')
{
for (j=1;j<n && str[j]!='}';j++)
;
if (j==n)
goto bad;
string ds = str.Substring(1,j-1);
string s = (string)tks.defines[ds];
if (s==null)
m_sub = new ReCategory(tks,ds);
else
m_sub = new Regex(tks,p+1,s);
j++;
}
else
{ // simple character at start of regular expression
//7. Look to see if the string begins with a dot.
// If so, construct a CReDot, mark the . as used, and go to step 9.
if (str[0]=='.')
m_sub = new ReRange(tks,"[^\n]");
//8. At this point we conclude that there is a simple character at the start of the regular expression.
// Construct a ReStr for it, mark it as used, and go to step 9.
else
m_sub = new ReStr(tks,str[0]);
j = 1;
}
//9. If the string is exhausted, return.
// We have a simple Regex whose m_sub contains what we can constructed.
if (j>=n)
return;
//10. If the next character is a ? , *, or +, construct a CReOpt, CReStart, or CRePlus respectively
// out of m_sub, and make m_sub point to this new class instead. Mark the character as used.
if (str[j]=='?')
{
m_sub = new ReOpt(m_sub);
j++;
}
else if (str[j]=='*')
{
m_sub = new ReStar(m_sub);
j++;
}
else if (str[j]=='+')
{
m_sub = new RePlus(m_sub);
j++;
}
// 11. If the string is exhausted, return.
if (j>=n)
return;
// 12. If the next character is a | , build a ReAlt using the m_sub we have and the rest of the string.
if (str[j]=='|')
m_sub = new ReAlt(tks,m_sub,p+j+1,str.Substring(j+1,n-j-1));
// 13. Otherwise build a ReCat using the m_sub we have and the rest of the string.
else if (j<n)
m_sub = new ReCat(tks,m_sub,p+j,str.Substring(j,n-j));
return;
bad:
tks.erh.Error(new CSToolsFatalException(1,tks.sourceLineInfo(p),str,"ill-formed regular expression "+str));
}
/*
* Construct a Regex from a given string
*
* 1. First examine the given string.
* If it is empty, there is nothing to do, so return (having cleared m_sub as a precaution).
* 2. Look to see if the string begins with a bracket ( . If so, find the matching ) .
* This is not as simple as it might be because )s inside quotes or [] or escaped will not count.
* Recursively call the constructor for the regular expression between the () s.
* Mark everything up to the ) as used, and go to step 9.
* 3. Look to see if the string begins with a bracket [ . If so, find the matching ] , watching for escapes.
* Construct a ReRange for everything between the []s.
* Mark everything up to the ] as used, and go to step 9.
* 4. Look to see if the string begins with a ' or " . If so, build the contents interpreting
* escaped special characters correctly, until the matching quote is reached.
* Construct a ReStr for the contents, mark everything up to the final quote as used, and go to step 9.
* 4a. Look to see if the string begins with a U' or U" . If so, build the contents interpreting
* escaped special characters correctly, until the matching quote is reached.
* Construct a ReUStr for the contents, mark everything up to the final quote as used, and go to step 9.
* 5. Look to see if the string begins with a \ .
* If so, build a ReStr for the next character (special action for ntr),
* mark it as used, and go to step 9.
* 6. Look to see if the string begins with a { .
* If so, find the matching }, lookup the symbolic name in the definitions table,
* recursively call this constructor on the contents,
* mark everything up to the } as used, and go to step 9.
* 7. Look to see if the string begins with a dot.
* If so, construct a ReRange("^\n"), mark the . as used, and go to step 9.
* 8. At this point we conclude that there is a simple character at the start of the regular expression.
* Construct a ReStr for it, mark it as used, and go to step 9.
* 9. If the string is exhausted, return.
* We have a simple Regex whose m_sub contains what we can constructed.
* 10. If the next character is a ? , *, or +, construct a ReOpt, ReStart, or RePlus respectively
* out of m_sub, and make m_sub point to this new class instead. Mark the character as used.
* 11. If the string is exhausted, return.
* 12. If the next character is a | , build a ReAlt using the m_sub we have and the rest of the string.
* 13. Otherwise build a ReCat using the m_sub we have and the rest of the string.
*/
public Regex(TokensGen tks, int p, string str)
{
int n = str.Length;
int nlp = 0;
int lbrack = 0;
int quote = 0;
int j;
char ch;
//1. First examine the given string.
// If it is empty, there is nothing to do, so return (having cleared m_sub as a precaution).
m_sub = null;
if (n == 0)
{
return;
}
//2. Look to see if the string begins with a bracket ( . If so, find the matching ) .
// This is not as simple as it might be because )s inside quotes or [] or escaped will not count.
// Recursively call the constructor for the regular expression between the () s.
// Mark everything up to the ) as used, and go to step 9.
else if (str[0] == '(')
{ // identify a bracketed expression
for (j = 1; j < n; j++)
{
if (str[j] == '\\')
{
j++;
}
else if (str[j] == ']' && lbrack > 0)
{
lbrack = 0;
}
else if (lbrack > 0)
{
continue;
}
else if (str[j] == '"' || str[j] == '\'')
{
if (quote == str[j])
{
quote = 0;
}
else if (quote == 0)
{
quote = str[j];
}
}
else if (quote > 0)
{
continue;
}
else if (str[j] == '[')
{
lbrack++;
}
else if (str[j] == '(')
{
nlp++;
}
else if (str[j] == ')' && nlp-- == 0)
{
break;
}
}
if (j == n)
{
goto bad;
}
m_sub = new Regex(tks, p + 1, str.Substring(1, j - 1));
j++;
//3. Look to see if the string begins with a bracket [ . If so, find the matching ] , watching for escapes.
// Construct a ReRange for everything between the []s.
// Mark everything up to the ] as used, and go to step 9.
}
else if (str[0] == '[')
{ // range of characters
for (j = 1; j < n && str[j] != ']'; j++)
{
if (str[j] == '\\')
{
j++;
}
}
if (j == n)
{
goto bad;
}
m_sub = new ReRange(tks, str.Substring(0, j + 1));
j++;
}
//4. Look to see if the string begins with a ' or " . If so, build the contents interpreting
// escaped special characters correctly, until the matching quote is reached.
// Construct a CReStr for the contents, mark everything up to the final quote as used, and go to step 9.
else if (str[0] == '\'' || str[0] == '"')
{ // quoted string needs special treatment
StringBuilder qs = new StringBuilder();
for (j = 1; j < n && str[j] != str[0]; j++)
{
if (str[j] == '\\')
{
switch (str[++j])
{
case 'n': qs.Append('\n'); break;
case 'r': qs.Append('\r'); break;
case 't': qs.Append('\t'); break;
case 'v': qs.Append('\v'); break;
case '\\': qs.Append('\\'); break;
case '\'': qs.Append('\''); break;
case '0': qs.Append((char)0); break; // 4.7f
case '"': qs.Append('"'); break;
case '\n': break;
default: qs.Append(str[j]); break;
}
}
else
{
qs.Append(str[j]);
}
}
if (j == n)
{
goto bad;
}
j++;
m_sub = new ReStr(tks, qs.ToString());
}
//4a. Look to see if the string begins with a U' or U" . If so, build the contents interpreting
// escaped special characters correctly, until the matching quote is reached.
// Construct a ReUStr for the contents, mark everything up to the final quote as used, and go to step 9.
else if (str.StartsWith("U\"") || str.StartsWith("U'"))
{ // quoted string needs special treatment
StringBuilder qs = new StringBuilder();
for (j = 2; j < n && str[j] != str[1]; j++)
{
if (str[j] == '\\')
{
switch (str[++j])
{
case 'n': qs.Append('\n'); break;
case 'r': qs.Append('\r'); break;
case 't': qs.Append('\t'); break;
case 'v': qs.Append('\v'); break;
case '\\': qs.Append('\\'); break;
case '\'': qs.Append('\''); break;
case '"': qs.Append('"'); break;
case '\n': break;
default: qs.Append(str[j]); break;
}
}
else
{
qs.Append(str[j]);
}
}
if (j == n)
{
goto bad;
}
j++;
m_sub = new ReUStr(tks, qs.ToString());
}
//5. Look to see if the string begins with a \ .
// If so, build a ReStr for the next character (special action for ntr),
// mark it as used, and go to step 9.
else if (str[0] == '\\')
{
switch (ch = str[1])
{
case 'n': ch = '\n'; break;
case 't': ch = '\t'; break;
case 'r': ch = '\r'; break;
case 'v': ch = '\v'; break;
}
m_sub = new ReStr(tks, ch);
j = 2;
//6. Look to see if the string begins with a { .
// If so, find the matching }, lookup the symbolic name in the definitions table,
// recursively call this constructor on the contents,
// mark everything up to the } as used, and go to step 9.
}
else if (str[0] == '{')
{
for (j = 1; j < n && str[j] != '}'; j++)
{
;
}
if (j == n)
{
goto bad;
}
string ds = str.Substring(1, j - 1);
string s = (string)tks.defines[ds];
if (s == null)
{
m_sub = new ReCategory(tks, ds);
}
else
{
m_sub = new Regex(tks, p + 1, s);
}
j++;
}
else
{ // simple character at start of regular expression
//7. Look to see if the string begins with a dot.
// If so, construct a CReDot, mark the . as used, and go to step 9.
if (str[0] == '.')
{
m_sub = new ReRange(tks, "[^\n]");
}
//8. At this point we conclude that there is a simple character at the start of the regular expression.
// Construct a ReStr for it, mark it as used, and go to step 9.
else
{
m_sub = new ReStr(tks, str[0]);
}
j = 1;
}
//9. If the string is exhausted, return.
// We have a simple Regex whose m_sub contains what we can constructed.
if (j >= n)
{
return;
}
//10. If the next character is a ? , *, or +, construct a CReOpt, CReStart, or CRePlus respectively
// out of m_sub, and make m_sub point to this new class instead. Mark the character as used.
if (str[j] == '?')
{
m_sub = new ReOpt(m_sub);
j++;
}
else if (str[j] == '*')
{
m_sub = new ReStar(m_sub);
j++;
}
else if (str[j] == '+')
{
m_sub = new RePlus(m_sub);
j++;
}
// 11. If the string is exhausted, return.
if (j >= n)
{
return;
}
// 12. If the next character is a | , build a ReAlt using the m_sub we have and the rest of the string.
if (str[j] == '|')
{
m_sub = new ReAlt(tks, m_sub, p + j + 1, str.Substring(j + 1, n - j - 1));
}
// 13. Otherwise build a ReCat using the m_sub we have and the rest of the string.
else if (j < n)
{
m_sub = new ReCat(tks, m_sub, p + j, str.Substring(j, n - j));
}
return;
bad:
tks.erh.Error(new CSToolsFatalException(1, tks.sourceLineInfo(p), str, "ill-formed regular expression " + str));
}
