48 lines
1.7 KiB
Plaintext
48 lines
1.7 KiB
Plaintext
_version_: PLT version checking
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===============================
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The version collection contains several version-related pieces that
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are used by PLT Scheme. First, the "check.ss" module provides a
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single function:
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> (check-version)
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This procedure checks the currently available version on the PLT
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website (doanload.plt-scheme.org), and returns a value that indicates
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your current state -- one of these:
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* `ok
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You're fine.
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* `(ok-but ,version)
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You have a fine stable version, but note that there is a newer
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alpha version available
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* `(newer ,version)
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You have an old version, please upgrade to `version'
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* `(newer ,version ,alpha)
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You have an old-but-stable version, please upgrade to `version';
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you may consider also the newer alpha version
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* `(error ,message [,additional-info])
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An error occurred, the message is a string that indicates the
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error.
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The third (optional) value is a string that can be shown as the
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system error that happened. This string will always be
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parenthesized, so `message' is a short error and
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`(string-append message " " additional-info)' is a verbose one.
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The second functionality that is provided by this collection is in the
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_patchlevel_ module. This module provides a single value:
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> patchlevel
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which is an integer that indicates the current patch level. This is
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normally zero, but may be updated by patches to DrScheme.
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Finally, the "tool.ss" makes DrScheme use both features:
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* the patchlevel appears as a version `pN' suffix in DrScheme (but the
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binary version as reported by `(version)' is not changed);
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* it is possible to periodically check whether a new PLT Scheme
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distribution is available for download.
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