MESSAGE
| DATE | 2016-05-08 |
| FROM | Ruben Safir
|
| SUBJECT | Subject: [Hangout-NYLXS] Your version of tYpEcheCkingvIsiTor is confusing me
|
So for ConvertToIR.java
So we have operators, like the + operator for instructions.
So the NODE can have one of three types
a string, in integer or a float. So I'm
trying to do it like you did it which means I need to know
if it is a string... so that is I think easy because the node
remembers its type when you run the constructor
/**
* Run the converter on the parse tree after it has been type-checked.
*/
public ConvertToIR(TypeChecker typeChecker) {
this.typeChecker = typeChecker;
this.typeChecker.getParseTree().accept(this);
}
So you used this, and I think that now wee have to all the types and
accessory methods through typeChecker, which is a ctx.
So now I think I can do this, but I'm not sure, because ConvertToIR
inherits from the same base visitor as TypeChecker, but they are not the
same object. The parsetrees are the same so I think I can do this
63 ¦ Type base_type = typeChecker.GetNodeType(ctx);
64 ¦ Type current_type = typeChecker.GetCoercion(ctx);
65 ¦ Address a;
or more exactly
55 ¦-at-Override
56 ¦public Address visitOpExpr(CalcLangParser.OpExprContext ctx) {
57 ¦ ¦ // ASSUME this represents addition.
58 ¦ ¦ // ASSUME these are integers
59
60 ¦ String op = ctx.op.getText();
61 ¦ ¦ Address left = ctx.left.accept(this);
62 ¦ ¦ Address right = ctx.right.accept(this);
63 ¦ Type base_type = typeChecker.GetNodeType(ctx);
64 ¦ Type current_type = typeChecker.GetCoercion(ctx);
65 ¦ Address a;
66
67 ¦ if(current_type == null ){
68 ¦ current_type = base_type;
69 ¦ }
If not, saving the Type values in TypChecker is fabulously useless.
__But that is not what really is confusing me :) (Lights Camera, Strum
Alice's Restaurant and Hum)__
Your version of TypeChecker has the following code and I'm trying to
follow this code syntax for ConvertToIR
-at-Override
public Type visitOpExpr(CalcLangParser.OpExprContext ctx) {
Type leftType = ctx.left.accept(this);
Type rightType = ctx.right.accept(this);
// OpExpr is used for arithmetic, relational, equality, logical
String op = ctx.op.getText();
switch(op)
{
case "^":case "*":case "/":case "+":case "-": // arithmetic
{
if(leftType == Type.STRING && rightType == Type.STRING
&& op.equals("+"))
{
return trace(ctx, Type.STRING);
}
if (!leftType.isNumeric()) {
return typeMismatch(ctx, leftType, Type.FLOAT);
}
if (!rightType.isNumeric()) {
return typeMismatch(ctx, rightType, Type.FLOAT);
}
Type resultType = unify(ctx.left, leftType, ctx.right,
rightType);
return trace(ctx, resultType);
}
Type.isNumeric is defined (really do we have enough files and classes
here) in Class Type.java
public boolean isNumeric() {
return leastUpperBound(FLOAT) == FLOAT;
}
}
UGGGG
Good thing ctags is now working:
/**
* The types form a hierarchy, with ERROR at the root.
* -at-return The least upper bound of this and that.
*/
public Type leastUpperBound(Type that) {
if(this == that)
return this;
if((this == INT && that == FLOAT)
||(this == FLOAT && that == INT))
return FLOAT;
return ERROR;
}
SO WHAT'S HAPPENING? isNumeric() is calling leastUpperBound with FLOAT.
Is this a type? This is a reference to an instance of a class. What
class? It depends if it is inherited or not. Worse this is an enum and
not even a standard class. Can you guarantee "this" will be a Type or a
the enum values?
This is more than an hour to take this apart.
in ConvertToIR, I need to make Address and Instruction
I need to know if the node is an INT or a FLOAT and then
convert it to and Instruction. I need to know if that node
Type is a Float or an Int ... different instructions.
--
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
http://www.mrbrklyn.com
DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
http://www.nylxs.com - Leadership Development in Free Software
http://www2.mrbrklyn.com/resources - Unpublished Archive
http://www.coinhangout.com - coins!
http://www.brooklyn-living.com
Being so tracked is for FARM ANIMALS and and extermination camps,
but incompatible with living as a free human being. -RI Safir 2013
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