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bitbake: bitbake-user-manual: Updated the "Inline Python Variable Expansion" section.
Fixes [YOCTO #9984] Added a small note to the bottom to help clarify. (Bitbake rev: 64bf49826088c56b739ed971251f05b4564c712e) Signed-off-by: Scott Rifenbark <srifenbark@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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Richard Purdie
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@@ -316,7 +316,7 @@
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</literallayout>
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</literallayout>
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<note>
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<note>
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It is never necessary to use "+=" together with "_append".
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It is never necessary to use "+=" together with "_append".
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The following sequence of assignments appepnds "barbaz" to
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The following sequence of assignments appends "barbaz" to
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<filename>FOO</filename>:
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<filename>FOO</filename>:
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<literallayout class='monospaced'>
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<literallayout class='monospaced'>
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FOO_append = "bar"
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FOO_append = "bar"
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@@ -401,6 +401,21 @@
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PN = "${@bb.parse.BBHandler.vars_from_file(d.getVar('FILE', False),d)[0] or 'defaultpkgname'}"
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PN = "${@bb.parse.BBHandler.vars_from_file(d.getVar('FILE', False),d)[0] or 'defaultpkgname'}"
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PV = "${@bb.parse.BBHandler.vars_from_file(d.getVar('FILE', False),d)[1] or '1.0'}"
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PV = "${@bb.parse.BBHandler.vars_from_file(d.getVar('FILE', False),d)[1] or '1.0'}"
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</literallayout>
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</literallayout>
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<note>
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Inline Python expressions work just like variable expansions
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insofar as the "=" and ":=" operators are concerned.
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Given the following assignment, <filename>foo()</filename>
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is called each time <filename>FOO</filename> is expanded:
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<literallayout class='monospaced'>
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FOO = "${@foo()}"
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</literallayout>
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Contrast this with the following immediate assignment, where
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<filename>foo()</filename> is only called once, while the
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assignment is parsed:
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<literallayout class='monospaced'>
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FOO := "${@foo()}"
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</literallayout>
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</note>
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</para>
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</para>
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</section>
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</section>
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