Add support for Module.

corywalker · Jul 5, 2017 · 1710acd · 1710acd
1 parent 75093a8
commit 1710acd
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Showing 4 changed files with 113 additions and 2 deletions.
diff --git a/expreduce/builtin_system.go b/expreduce/builtin_system.go
@@ -526,5 +526,104 @@ func GetSystemDefinitions() (defs []Definition) {
 			return &Symbol{"$Failed"}
 		},
 	})
+	defs = append(defs, Definition{
+		Name:  "Module",
+		Usage: "`Module[{locals}, expr]` evaluates `expr` with the local variables `locals`.",
+		Attributes: []string{"HoldAll"},
+		legacyEvalFn: func(this *Expression, es *EvalState) Ex {
+			// Coarse parsing of arguments.
+			if len(this.Parts) != 3 {
+				return this
+			}
+			locals, localsIsList := HeadAssertion(this.Parts[1], "List")
+			if !localsIsList {
+				return this
+			}
+			mnExpr, mnIsDef := es.GetSymDef("$ModuleNumber")
+			if !mnIsDef {
+				return this
+			}
+			mnInteger, mnIsInt := mnExpr.(*Integer)
+			if !mnIsInt {
+				return this
+			}
+			mn := mnInteger.Val.Int64()
+
+			// Parse locals into a struct
+			type parsedLocal struct {
+				sym *Symbol
+				uniqueName string
+				setValue Ex
+				isSet bool
+				isSetDelayed bool
+			}
+			var parsedLocals []parsedLocal
+			for _, localEx := range locals.Parts[1:] {
+				pl := parsedLocal{}
+				symEx := localEx
+				localSet, localIsSet := HeadAssertion(localEx, "Set")
+				pl.isSet = localIsSet
+				localSetDelayed, localIsSetDelayed := HeadAssertion(localEx, "SetDelayed")
+				pl.isSetDelayed = localIsSetDelayed
+				if localIsSet && len(localSet.Parts) == 3 {
+					symEx = localSet.Parts[1]
+					pl.setValue = localSet.Parts[2]
+				}
+				if localIsSetDelayed && len(localSetDelayed.Parts) == 3 {
+					symEx = localSetDelayed.Parts[1]
+					pl.setValue = localSetDelayed.Parts[2]
+				}
+				localSym, localIsSym := symEx.(*Symbol)
+				pl.sym = localSym
+				if !localIsSym {
+					return this
+				}
+				parsedLocals = append(parsedLocals, pl)
+			}
+
+			// Find the next ModuleNumber to use.
+			tryingNew := true
+			for tryingNew {
+				tryingNew = false
+				for i := range parsedLocals {
+					parsedLocals[i].uniqueName = fmt.Sprintf("%v$%v", parsedLocals[i].sym.Name, mn)
+					if es.IsDef(parsedLocals[i].uniqueName) {
+						mn += 1
+						tryingNew = true
+						break
+					}
+				}
+			}
+			es.Define(&Symbol{"$ModuleNumber"}, &Integer{big.NewInt(mn+1)})
+			toReturn := this.Parts[2]
+			for _, pl := range parsedLocals {
+				if pl.isSet || pl.isSetDelayed {
+					rhs := pl.setValue
+					if pl.isSet {
+						rhs = rhs.Eval(es)
+					}
+					es.defined[pl.uniqueName] = Def{
+						downvalues: []Expression{*NewExpression([]Ex{&Symbol{"Rule"}, &Symbol{pl.uniqueName}, rhs})},
+					}
+				} else {
+					es.defined[pl.uniqueName] = Def{}
+				}
+				toReturn = ReplaceAll(toReturn,
+					NewExpression([]Ex{
+						&Symbol{"Rule"},
+						&Symbol{pl.sym.Name},
+						&Symbol{pl.uniqueName},
+					}), es, EmptyPD(), "")
+			}
+			return toReturn
+		},
+		Tests: []TestInstruction{
+			&SameTest{"{t$1,j$1,2}", "$ModuleNumber=1;Module[{t,j},{t,j,$ModuleNumber}]"},
+			&SameTest{"{t$2,j$2,3}", "$ModuleNumber=1;Module[{t,j},{t,j,$ModuleNumber}]"},
+			&SameTest{"{t$4,j$4,5}", "$ModuleNumber=1;t$3=test;Module[{t,j},{t,j,$ModuleNumber}]"},
+			&SameTest{"{t$8,2,9}", "$ModuleNumber=8;t$3=test;Module[{t,j=2},{t,j,$ModuleNumber}]"},
+			&SameTest{"{t$9,2,10}", "$ModuleNumber=8;t$3=test;Module[{t,j:=2},{t,j,$ModuleNumber}]"},
+		},
+	})
 	return
 }
diff --git a/expreduce/evalstate.go b/expreduce/evalstate.go
@@ -124,9 +124,13 @@ func NewEvalStateNoLog(loadAllDefs bool) *EvalState {
 	return &es
 }
 
-func (this *EvalState) GetDef(name string, lhs Ex) (Ex, bool, *Expression) {
+func (this *EvalState) IsDef(name string) bool {
 	_, isd := this.defined[name]
-	if !isd {
+	return isd
+}
+
+func (this *EvalState) GetDef(name string, lhs Ex) (Ex, bool, *Expression) {
+	if !this.IsDef(name) {
 		return nil, false, nil
 	}
 	this.Debugf("Inside GetDef(\"%s\",%s)", name, lhs)
@@ -156,6 +160,12 @@ func (this *EvalState) GetDef(name string, lhs Ex) (Ex, bool, *Expression) {
 	return nil, false, nil
 }
 
+func (this *EvalState) GetSymDef(name string) (Ex, bool) {
+	sym := &Symbol{name}
+	symDef, isDef, _ := this.GetDef(name, sym)
+	return symDef, isDef
+}
+
 func (this *EvalState) Define(lhs Ex, rhs Ex) {
 	if this.IsFrozen() {
 		return

diff --git a/expreduce/resources/init.er b/expreduce/resources/init.er
@@ -1,3 +1,4 @@
 (* This file is executed upon initialization. *)
 SeedRandom[UnixTime[]];
 $Version = "Expreduce";
+$ModuleNumber = 1;
diff --git a/expreduce/resources/power.er b/expreduce/resources/power.er
@@ -20,6 +20,7 @@ PolynomialQ[p_.*v_^Optional[exp_Integer], v_] :=
   If[FreeQ[p, v] && Positive[exp], True, False];
 PolynomialQ[p_, v_] := If[FreeQ[p, v], True, False];
 
+(* Needs PrependTo and DeleteDuplicates and Module *)
 Exponent[expr_/p_Plus,var_,head_]:=Exponent[expr,var,head];
 Exponent[expr_,var_,head_]:=Module[{e=expr,v=var,h=head,theCases,toCheck},
     toCheck=expr//Expand;