//Compile a given expression as a pattern. If match fails proceed to failLab.
private void CompilePattern(int sysVar, ElaExpression exp, Label failLab, bool allowBang, bool forceStrict)
{
AddLinePragma(exp);
switch (exp.Type)
{
case ElaNodeType.LazyLiteral:
{
var n = (ElaLazyLiteral)exp;
//Normally this flag is set when everything is already compiled as lazy.
if (forceStrict)
CompilePattern(sysVar, n.Expression, failLab, allowBang, forceStrict);
else
CompileLazyPattern(sysVar, exp, allowBang);
}
break;
case ElaNodeType.FieldReference:
{
//We treat this expression as a constructor with a module alias
var n = (ElaFieldReference)exp;
var fn = n.FieldName;
var alias = n.TargetObject.GetName();
PushVar(sysVar);
if (n.TargetObject.Type != ElaNodeType.NameReference)
AddError(ElaCompilerError.InvalidPattern, n, FormatNode(n));
else
EmitSpecName(alias, "$$$$" + fn, n, ElaCompilerError.UndefinedName);
cw.Emit(Op.Skiptag);
cw.Emit(Op.Br, failLab);
}
break;
case ElaNodeType.NameReference:
{
//Irrefutable pattern, always binds expression to a name, unless it is
//a constructor pattern
var n = (ElaNameReference)exp;
//Bang pattern are only allowed in constructors and functions
if (n.Bang && !allowBang)
{
AddError(ElaCompilerError.BangPatternNotValid, exp, FormatNode(exp));
AddHint(ElaCompilerHint.BangsOnlyFunctions, exp);
}
if (n.Uppercase) //This is a constructor
{
if (sysVar != -1)
PushVar(sysVar);
EmitSpecName(null, "$$$$" + n.Name, n, ElaCompilerError.UndefinedName);
//This op codes skips one offset if an expression
//on the top of the stack has a specified tag.
cw.Emit(Op.Skiptag);
cw.Emit(Op.Br, failLab);
}
else
{
var newV = false;
var addr = AddMatchVariable(n.Name, n, out newV);
//This is a valid situation, it means that the value is
//already on the top of the stack.
if (sysVar > -1 && newV)
PushVar(sysVar);
if (n.Bang)
cw.Emit(Op.Force);
//The binding is already done, so just idle.
if (newV)
PopVar(addr);
}
}
break;
case ElaNodeType.UnitLiteral:
{
//Unit pattern is redundant, it is essentially the same as checking
//the type of an expression which is what we do here.
PushVar(sysVar);
cw.Emit(Op.Force);
cw.Emit(Op.PushI4, (Int32)ElaTypeCode.Unit);
cw.Emit(Op.Ctype);
//Types are not equal, proceed to fail.
cw.Emit(Op.Brfalse, failLab);
}
break;
case ElaNodeType.Primitive:
{
var n = (ElaPrimitive)exp;
//Compare a given value with a primitive
PushVar(sysVar);
PushPrimitive(n.Value);
cw.Emit(Op.Cneq);
//Values not equal, proceed to fail.
cw.Emit(Op.Brtrue, failLab);
}
break;
case ElaNodeType.As:
{
var n = (ElaAs)exp;
CompilePattern(sysVar, n.Expression, failLab, allowBang, false /*forceStrict*/);
var newV = false;
var addr = AddMatchVariable(n.Name, n, out newV);
PushVar(sysVar);
PopVar(addr);
}
break;
case ElaNodeType.Placeholder:
//This is a valid situation, it means that the value is
//already on the top of the stack. Otherwise - nothing have to be done.
if (sysVar == -1)
cw.Emit(Op.Pop);
break;
case ElaNodeType.RecordLiteral:
{
var n = (ElaRecordLiteral)exp;
CompileRecordPattern(sysVar, n, failLab, allowBang);
}
break;
case ElaNodeType.TupleLiteral:
{
var n = (ElaTupleLiteral)exp;
CompileTuplePattern(sysVar, n, failLab, allowBang);
}
break;
case ElaNodeType.Juxtaposition:
{
//An infix pattern, currently the only case is head/tail pattern.
var n = (ElaJuxtaposition)exp;
CompileComplexPattern(sysVar, n, failLab, allowBang);
}
break;
case ElaNodeType.ListLiteral:
{
var n = (ElaListLiteral)exp;
//We a have a nil pattern '[]'
if (!n.HasValues())
{
PushVar(sysVar);
cw.Emit(Op.Isnil);
cw.Emit(Op.Brfalse, failLab);
}
else
{
//We don't want to write the same compilation logic twice,
//so here we transform a list literal into a chain of function calls, e.g.
//[1,2,3] goes to 1::2::3::[] with a mandatory nil at the end.
var len = n.Values.Count;
ElaExpression last = ElaListLiteral.Empty;
var fc = default(ElaJuxtaposition);
//Loops through all elements in literal backwards
for (var i = 0; i < len; i++)
{
var nn = n.Values[len - i - 1];
fc = new ElaJuxtaposition();
fc.SetLinePragma(nn.Line, nn.Column);
fc.Parameters.Add(nn);
fc.Parameters.Add(last);
last = fc;
}
//Now we can compile it as head/tail pattern
CompilePattern(sysVar, fc, failLab, allowBang, false /*forceStrict*/);
}
}
break;
default:
AddError(ElaCompilerError.InvalidPattern, exp, FormatNode(exp));
break;
}
}
private void ProcessDoBlock(ElaExpression cexp1, ElaExpression cexp2, ref ElaExpression rootExp)
{
var eqt = default(ElaJuxtaposition);
var lam = default(ElaLambda);
var letb = default(ElaLetBinding);
if (cexp2 == null)
{
cexp2 = cexp1;
cexp1 = new ElaPlaceholder();
}
if (rootExp.Type == ElaNodeType.Juxtaposition)
eqt = (ElaJuxtaposition)rootExp;
else if (rootExp.Type == ElaNodeType.Lambda)
{
lam = (ElaLambda)rootExp;
eqt = lam.Right as ElaJuxtaposition;
}
else if (rootExp.Type == ElaNodeType.LetBinding)
{
letb = (ElaLetBinding)rootExp;
eqt = letb.Expression as ElaJuxtaposition;
}
else if (rootExp.Type != ElaNodeType.None)
{
eqt = new ElaJuxtaposition { Spec = true };
eqt.SetLinePragma(cexp1.Line, cexp1.Column);
eqt.Parameters.Add(null);
eqt.Parameters.Add(rootExp);
}
if (eqt != null && !eqt.Spec)
{
var eqt2 = new ElaJuxtaposition();
eqt2.SetLinePragma(eqt.Line, eqt.Column);
eqt2.Target = new ElaNameReference(t) { Name = ">>-" };
eqt2.Parameters.Add(null);
eqt2.Parameters.Add(eqt);
eqt = eqt2;
}
if (eqt != null && eqt.Parameters.Count == 2)
{
if (eqt.Parameters[0] == null)
{
eqt.Target = new ElaNameReference(t) { Name = ">>=" };
var lambda = new ElaLambda();
lambda.SetLinePragma(cexp2.Line, cexp2.Column);
lambda.Left = new ElaPlaceholder();
var lambda2 = new ElaLambda();
lambda2.SetLinePragma(cexp2.Line, cexp2.Column);
lambda2.Left = cexp1;
var eqt1 = new ElaJuxtaposition { Spec = true };
eqt1.SetLinePragma(cexp2.Line, cexp2.Column);
eqt1.Target = new ElaNameReference(t) { Name = ">>=" };
eqt1.Parameters.Add(cexp2);
eqt1.Parameters.Add(lambda2);
lambda.Right = eqt1;
eqt.Parameters[0] = eqt.Parameters[1];
eqt.Parameters[1] = lambda;
rootExp = lambda2;
}
else
{
throw new Exception("Unable to process do-notation.");
}
}
else
{
if (eqt == null)
{
eqt = new ElaJuxtaposition { Spec = true };
eqt.SetLinePragma(cexp1.Line, cexp1.Column);
if (lam != null)
lam.Right = eqt;
else if (letb != null)
letb.Expression = eqt;
}
eqt.Target = new ElaNameReference(t) { Name = ">>=" };
eqt.Parameters.Add(cexp2);
var lambda = new ElaLambda();
lambda.SetLinePragma(cexp2.Line, cexp2.Column);
lambda.Left = cexp1;
eqt.Parameters.Add(lambda);
rootExp = lambda;
}
}
private ElaExpression ValidateDoBlock(ElaExpression exp)
{
if (exp.Type == ElaNodeType.Juxtaposition && ((ElaJuxtaposition)exp).Parameters[0] == null)
{
var ext = ((ElaJuxtaposition)exp).Parameters[1];
var ctx = default(ElaContext);
if (ext.Type == ElaNodeType.Context)
{
ctx = (ElaContext)ext;
ext = ctx.Expression;
}
var eqt = new ElaJuxtaposition { Spec = true };
eqt.SetLinePragma(exp.Line, exp.Column);
eqt.Target = new ElaNameReference(t) { Name = ">>=" };
eqt.Parameters.Add(ext);
var jux = new ElaJuxtaposition();
jux.SetLinePragma(exp.Line, exp.Column);
jux.Target = new ElaNameReference { Name = "point" };
jux.Parameters.Add(new ElaUnitLiteral());
eqt.Parameters.Add(new ElaLambda { Left = new ElaPlaceholder(), Right = jux });
if (ctx != null)
{
ctx.Expression = eqt;
exp = ctx;
}
else
exp = eqt;
}
var root = exp;
while (true)
{
if (exp.Type == ElaNodeType.Juxtaposition)
{
var juxta = (ElaJuxtaposition)exp;
if (juxta.Parameters.Count == 2)
{
juxta.Parameters[0] = Reduce(juxta.Parameters[0], juxta);
juxta.Parameters[1] = Reduce(juxta.Parameters[1], juxta);
exp = juxta.Parameters[1];
}
else
break;
}
else if (exp.Type == ElaNodeType.LetBinding)
{
var lb = (ElaLetBinding)exp;
lb.Expression = Reduce(lb.Expression, lb);
exp = lb.Expression;
}
else if (exp.Type == ElaNodeType.Lambda)
{
var lb = (ElaLambda)exp;
lb.Right = Reduce(lb.Right, lb);
if (lb.Left.Type != ElaNodeType.NameReference &&
lb.Left.Type != ElaNodeType.Placeholder)
{
var em = new ElaMatch();
em.SetLinePragma(lb.Left.Line, lb.Left.Column);
em.Expression = new ElaNameReference { Name = "$x01" };
em.Entries = new ElaEquationSet();
var eq1 = new ElaEquation();
eq1.SetLinePragma(lb.Left.Line, lb.Left.Column);
eq1.Left = lb.Left;
eq1.Right = lb.Right;
em.Entries.Equations.Add(eq1);
var eq2 = new ElaEquation();
eq2.SetLinePragma(lb.Left.Line, lb.Left.Column);
eq2.Left = new ElaNameReference { Name = "$x02" };
var errExp = new ElaJuxtaposition();
errExp.SetLinePragma(lb.Left.Line, lb.Left.Column);
errExp.Target = new ElaNameReference { Name = "failure" };
errExp.Parameters.Add(new ElaNameReference { Name = "$x02" });
eq2.Right = errExp;
em.Entries.Equations.Add(eq2);
lb.Left = new ElaNameReference { Name = "$x01" };
lb.Right = em;
exp = lb;
}
else
exp = lb.Right;
}
else
break;
}
var ret = new ElaLazyLiteral { Expression = root };
ret.SetLinePragma(root.Line, root.Column);
return ret;
}
//Compiling a regular function call.
private ExprData CompileFunctionCall(ElaJuxtaposition v, LabelMap map, Hints hints)
{
var ed = ExprData.Empty;
var bf = default(ElaNameReference);
var sv = default(ScopeVar);
if (!map.HasContext && TryOptimizeConstructor(v, map))
return ed;
if (!map.HasContext && v.Target.Type == ElaNodeType.NameReference)
{
bf = (ElaNameReference)v.Target;
sv = GetVariable(bf.Name, bf.Line, bf.Column);
//If the target is one of the built-in application function we need to transform this
//to a regular function call, e.g. 'x |> f' is translated into 'f x' by manually creating
//an appropriates AST node. This is done to simplify compilation - so that all optimization
//of a regular function call would be applied to pipes as well.
if ((sv.Flags & ElaVariableFlags.Builtin) == ElaVariableFlags.Builtin)
{
var k = (ElaBuiltinKind)sv.Data;
if (v.Parameters.Count == 2)
{
if (k == ElaBuiltinKind.BackwardPipe)
{
var fc = new ElaJuxtaposition { Target = v.Parameters[0] };
fc.SetLinePragma(v.Line, v.Column);
fc.Parameters.Add(v.Parameters[1]);
return CompileFunctionCall(fc, map, hints);
}
else if (k == ElaBuiltinKind.ForwardPipe)
{
var fc = new ElaJuxtaposition { Target = v.Parameters[1] };
fc.SetLinePragma(v.Line, v.Column);
fc.Parameters.Add(v.Parameters[0]);
return CompileFunctionCall(fc, map, hints);
}
else if (k == ElaBuiltinKind.LogicalOr)
{
CompileLogicalOr(v, v.Parameters[0], v.Parameters[1], map, hints);
return ed;
}
else if (k == ElaBuiltinKind.LogicalAnd)
{
CompileLogicalAnd(v, v.Parameters[0], v.Parameters[1], map, hints);
return ed;
}
else if (k == ElaBuiltinKind.Seq)
{
CompileSeq(v, v.Parameters[0], v.Parameters[1], map, hints);
return ed;
}
}
}
}
//We can't apply tail call optimization for the context bound call
var tail = (hints & Hints.Tail) == Hints.Tail && !map.HasContext;
var len = v.Parameters.Count;
//Compile arguments to which a function is applied
for (var i = 0; i < len; i++)
CompileExpression(v.Parameters[len - i - 1], map, Hints.None, v);
//If this a tail call and we effectively call the same function we are currently in,
//than do not emit an actual function call, just do a goto. (Tail recursion optimization).
if (tail && map.FunctionName != null && map.FunctionName == v.GetName() &&
map.FunctionParameters == len && map.FunctionScope == GetScope(map.FunctionName)
&& (sv.Flags & ElaVariableFlags.ClassFun) != ElaVariableFlags.ClassFun)
{
AddLinePragma(v);
cw.Emit(Op.Br, map.FunStart);
return ed;
}
if (bf != null)
{
if (v.Parameters[0].Type == ElaNodeType.Primitive &&
bf.Line == v.Parameters[0].Line && bf.Column + bf.Name.Length == v.Parameters[0].Column &&
((ElaPrimitive)v.Parameters[0]).Value.IsNegative())
{
var par = ((ElaPrimitive)v.Parameters[0]).Value.ToString();
AddWarning(ElaCompilerWarning.NegationAmbiguity, v, bf.Name, par);
AddHint(ElaCompilerHint.AddSpaceApplication, v, bf.Name, par, par.TrimStart('-'));
}
//The target is one of built-in functions and therefore can be inlined for optimization.
if ((sv.Flags & ElaVariableFlags.Builtin) == ElaVariableFlags.Builtin)
{
var kind = (ElaBuiltinKind)sv.Data;
var pars = BuiltinParams(kind);
//We inline built-ins only when all arguments are provided
//If this is not the case a built-in is compiled into a function in-place
//and than called.
if (len != pars)
{
AddLinePragma(bf);
CompileBuiltin(kind, v.Target, map, bf.Name);
if (v.FlipParameters)
cw.Emit(Op.Flip);
for (var i = 0; i < len; i++)
cw.Emit(Op.Call);
}
else
CompileBuiltinInline(kind, v.Target, map, hints);
return ed;
}
else
{
//Regular situation, just push a target name
AddLinePragma(v.Target);
PushVar(sv);
if ((sv.VariableFlags & ElaVariableFlags.Function) == ElaVariableFlags.Function)
ed = new ExprData(DataKind.FunParams, sv.Data);
else if ((sv.VariableFlags & ElaVariableFlags.ObjectLiteral) == ElaVariableFlags.ObjectLiteral)
ed = new ExprData(DataKind.VarType, (Int32)ElaVariableFlags.ObjectLiteral);
}
}
else
ed = CompileExpression(v.Target, map, Hints.None, v);
//Why it comes from AST? Because parser do not save the difference between pre-, post- and infix applications.
//However Ela does support left and right sections for operators - and for such cases an additional flag is used
//to signal about a section.
if (v.FlipParameters)
cw.Emit(Op.Flip);
//It means that we are trying to call "not a function". Ela is a dynamic language, still it's worth to generate
//a warning in such a case.
if (ed.Type == DataKind.VarType)
AddWarning(ElaCompilerWarning.FunctionInvalidType, v.Target, FormatNode(v.Target));
AddLinePragma(v);
for (var i = 0; i < len; i++)
{
var last = i == v.Parameters.Count - 1;
//Use a tail call if this function call is a tail expression and optimizations are enabled.
if (last && tail && opt)
cw.Emit(Op.Callt);
else
cw.Emit(Op.Call);
}
return ed;
}
