Error vocabulary

There's no way to expect complete uniformity of error reporting across
all steps, so I don't think we should try to make the error reporting
vocabulary very complicated.

I propose:

<err:errors name="stepname" type="p:steptype">
  <error code="pfx:localname">
    any wf content
  </error>
</errors>

Consider the following step:

  <p:xslt name="foo">
    <p:input port="stylesheet"><p:document href="style.xsl"/></p:input>
  </p:xslt>

If the style.xsl file fails because of the followng xsl:message

  <xsl:message terminate="yes">
    <xsl:text>You blew it, </xsl:text>
    <xsl:value-of select="$user"/>
  </xsl:message>

The step might generate the following errors:

<err:errors name="foo" type="p:xslt">
  <error code="p:error">You blew it, kid</error>
</err:errors>

Where "p:error" is the error code for "general error".

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | There is always some accident in the
http://nwalsh.com/            | best of things, whether thoughts or
                              | expressions or deeds. The memorable
                              | thought, the happy expression, the
                              | admirable deed are only partly
                              | yours.--Henry David Thoreau