private Rule parseUpdateRule(string pname, string rule, Declarations decls)
{
int len = 1;
int equal = rule.IndexOf(":=");
if (equal < 0)
{
equal = rule.IndexOf('=');
}
else
{
len = 2;
}
if (equal < 0)
{
throw new ParseException(String.Format("Invalid update rule '{0}'!", rule));
}
string varname = rule.Substring(0, equal).Trim();
string upexpr = rule.Substring(equal + len).Trim();
VarDecl vd = decls.getVar(varname);
if (vd == null)
{
throw new ParseException(String.Format("Unknown variable {0}!", varname));
}
string expr = String.Format("int _UPDATE_{0} = {1};", varname, upexpr);
Declarations newdecls = parseDeclarations(expr, decls);
Expression e = newdecls.getFirstDecl().Expr;
e.fold(newdecls);
return(new UpdateRule(varname, e));
}
private Rule parseSyncRule(string pname, string rule, Declarations decls)
{
SyncRule.Direction dir;
if (rule.EndsWith("?"))
{
dir = SyncRule.Direction.Receive;
}
else
if (rule.EndsWith("!"))
{
dir = SyncRule.Direction.Send;
}
else
{
throw new ParseException(String.Format("Synchronization rule '{0}' must end with '!' or '?'!"));
}
rule = rule.TrimEnd(new char[] { '?', '!' });
string expr = String.Format("chan _CHANNEL_ = {0};", rule);
Declarations newdecls = parseDeclarations(expr, decls);
Expression e = newdecls.getVar("_CHANNEL_").Expr;
e.fold(newdecls);
return(new SyncRule(e, dir));
}
private Rule parseGuardRule(string pname, string rule, Declarations decls)
{
string expr = String.Format("bool _GUARD_ = {0};", rule);
Declarations newdecls = parseDeclarations(expr, decls);
Expression e = newdecls.getVar("_GUARD_").Expr;
e.fold(newdecls);
return(new GuardRule(e));
}
public bool getExprValue(Expression expr, out int val)
{
val = 0;
expr.fold(this);
if (expr.Type != Expression.ExpType.Const)
{
return(false);
}
val = expr.Value;
return(true);
}
static bool getFoldedValue(Expression e, Declarations symtab, out int val)
{
val = 0;
if (e == null)
{
return(false);
}
e.fold(symtab);
if (e.Type != ExpType.Const)
{
return(false);
}
val = e.Value;
return(true);
}
static bool getFoldedBoolValue(Expression e, Declarations symtab, out bool val)
{
val = false;
if (e == null)
{
return(false);
}
e.fold(symtab);
if (e.Type != ExpType.ConstBool)
{
return(false);
}
val = e.Value != 0;
return(true);
}
