com.codetaco.math.token.TokVariable Maven / Gradle / Ivy

Go to download
package com.codetaco.math.token;

import com.codetaco.math.Equ;
import com.codetaco.math.EquPart;
import com.codetaco.math.ValueStack;

public class TokVariable extends TokOperand {
    boolean assignedByEquation;

    public TokVariable() {
        super();
        assignedByEquation = false;
    }

    @Override
    public boolean accepts(final char s) {
        return Character.isLetter(s) || Character.isDigit(s) || s == '_' || s == '.';
    }

    public String getName() {
        return super.toString();
    }

    public boolean isResetable() {
        return assignedByEquation;
    }

    @Override
    public EquPart morph() throws Exception {
        final EquPart fun = Equ.getInstance().function(this);
        if (fun == null) {
            return this;
        }
        return fun;
    }

    @Override
    public void resolve(final ValueStack values) throws Exception {
        if (getEqu().getSupport() == null) {
            throw new Exception("variables require support");
        }

        final Object obj = getEqu().getSupport().resolveVariable(
          getValue().toString().toLowerCase(),
          getEqu().getBaseDate());
        if (obj == null) {
            /*
             * The variable may not exist if it is the target of an assignment
             * operation. The variable will be created rather than resolved.
             * Further, variables are final.
             */
            values.push(this);
            assignedByEquation = true;
        } else {
            values.push(TokVariableWithValue.builder()
              .variable(this)
              .currentValue(obj)
              .build());
        }
    }

    @Override
    public String toString() {
        return "var(" + super.toString() + ")";
    }
}