Singular/Sources — pull request #212 by alexanderdreyer (2012-11-27 12:32:20+00:00)
Title: Avpoid multiple initialization  of 'shared' and 'reference' types

Since 'shared' and 'reference' types are deactivated by default, one has to ensure via
` system("shared")` or `system("reference")` that the command is available. Previously multiple calls would have generated (possible incompatible) types of the same name (and with the same properties though). The patch avoids that problem. The types are initialized only once.