uk.ac.ed.ph.snuggletex.dombuilding.MatrixHandler Maven / Gradle / Ivy

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/* $Id: MatrixHandler.java 525 2010-01-05 14:07:36Z davemckain $
 *
 * Copyright (c) 2010, The University of Edinburgh.
 * All Rights Reserved
 */
package uk.ac.ed.ph.snuggletex.dombuilding;

import uk.ac.ed.ph.snuggletex.definitions.CoreErrorCode;
import uk.ac.ed.ph.snuggletex.internal.DOMBuilder;
import uk.ac.ed.ph.snuggletex.internal.SnuggleParseException;
import uk.ac.ed.ph.snuggletex.tokens.CommandToken;
import uk.ac.ed.ph.snuggletex.tokens.EnvironmentToken;
import uk.ac.ed.ph.snuggletex.tokens.FlowToken;

import java.util.List;

import org.w3c.dom.Element;

/**
 * Handles the AMSLaTeX cases and the various matrix environments.
 *
 * This can only be used in MATH mode and generates a mtable as a result, wrapped inside
 * an mfenced for the matrix/cases delimiters as required.
 *
 * @author David McKain
 * @version $Revision: 525 $
 */
public final class MatrixHandler implements EnvironmentHandler {

  /** Fence Opener, which may be blank. null indicates "no opener and closer" */
  private final String opener;

  /** Fence Closer, which may be blank. null indicates "no opener and closer" */
  private final String closer;

  /**
   * Maximum number of allowed columns. (Used for cases environment, which is always 2 columns) Zero
   * signifies no restriction.
   */
  private final int maxColumns;

  public MatrixHandler() {
    this(0, null, null);
  }

  public MatrixHandler(final String opener, final String closer) {
    this(0, opener, closer);
  }

  public MatrixHandler(int maxColumns, final String opener, final String closer) {
    this.maxColumns = maxColumns;
    this.opener = opener;
    this.closer = closer;
  }

  public void handleEnvironment(DOMBuilder builder, Element parentElement, EnvironmentToken token)
      throws SnuggleParseException {
    /* Maybe create outer  */
    Element tableContainer;
    if (opener != null) {
      tableContainer = builder.appendMathMLElement(parentElement, "mfenced");
      tableContainer.setAttribute("open", opener);
      tableContainer.setAttribute("close", closer);
    } else {
      tableContainer = parentElement;
    }

    /* Compute the geometry of the table and make sure its content model is OK */
    int[] geometry = TabularHandler.computeTableDimensions(token.getContent());
    int numColumns = geometry[1];

    /* Now we generate the resulting  inside the  */
    Element mtableElement = builder.appendMathMLElement(tableContainer, "mtable");
    Element mtrElement, mtdElement;
    FlowToken columnToken;
    int rowColumns;
    for (FlowToken rowToken : token.getContent()) {
      mtrElement = builder.appendMathMLElement(mtableElement, "mtr");
      List columns = ((CommandToken) rowToken).getArguments()[0].getContents();
      rowColumns = columns.size();
      if (maxColumns > 0 && rowColumns > maxColumns) {
        /* Error: Each row in a this environment must have no more than NN columns */
        builder.appendOrThrowError(
            mtrElement,
            rowToken,
            CoreErrorCode.TDEMM0,
            token.getEnvironment().getTeXName(),
            maxColumns);
        continue;
      }
      for (int i = 0; i < numColumns && i < rowColumns; i++) {
        columnToken = columns.get(i);
        mtdElement = builder.appendMathMLElement(mtrElement, "mtd");
        builder.handleTokens(
            mtdElement, ((CommandToken) columnToken).getArguments()[0].getContents(), true);
      }
      /* Add empty  for missing columns */
      for (int i = 0; i < numColumns - rowColumns; i++) {
        builder.appendMathMLElement(mtrElement, "mtd");
      }
    }
  }
}