Allow CustomTarget's to be indexed

This allows a CustomTarget to be indexed, and the resulting indexed
value (a CustomTargetIndex type), to be used as a source in other
targets. This will confer a dependency on the original target, but only
inserts the source file returning by index the original target's
outputs. This can allow a CustomTarget that creates both a header and a
code file to have it's outputs split, for example.

Fixes #1470

1 files changed, 21 insertions, 0 deletions

diff --git a/docs/markdown/snippets/custom-target-index.md b/docs/markdown/snippets/custom-target-index.md
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index 0000000..10d7cf1
--- /dev/null
+++ b/docs/markdown/snippets/custom-target-index.md
@@ -0,0 +1,21 @@
+# Can index CustomTaget objects
+
+The `CustomTarget` object can now be indexed like an array. The resulting
+object can be used as a source file for other Targets, this will create a
+dependency on the original `CustomTarget`, but will only insert the generated
+file corresponding to the index value of the `CustomTarget`'s `output` keyword.
+
+    c = CustomTarget(
+      ...
+      output : ['out.h', 'out.c'],
+    )
+    lib1 = static_library(
+      'lib1',
+      [lib1_sources, c[0]],
+      ...
+    )
+    exec = executable(
+      'executable',
+      c[1],
+      link_with : lib1,
+    )