Implement pure functions.

[goals.git] / stdlib / prelude.gl

diff --git a/stdlib/prelude.gl b/stdlib/prelude.gl
index 5b8818a..f4ab20e 100644 (file)
--- a/stdlib/prelude.gl
+++ b/stdlib/prelude.gl
@@ -17,11 +17,11 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 # This file is included first and automatically in all Goalfiles
-# (unless you use --no-prelude).  It contains standard goals and
+# (unless you use --no-prelude).  It contains standard functions and
 # tactics.
 
 # The only tactic that ‘make’ has.
-tactic *file (filename) = {
+tactic *file (filename) = @{
     # Rebuild if the target file doesn't exist at all.
     test -f %filename || exit 99
 
@@ -33,6 +33,31 @@ tactic *file (filename) = {
 
 # This is a simpler tactic than the above since it will
 # rebuild if the file is missing, but not if it is older.
-tactic *exists (filename) = {
+tactic *exists (filename) = @{
     test -f %filename || exit 99
 }
+
+#----------------------------------------------------------------------
+# Text functions.
+
+# Sort + uniq a list.
+pure function sort (xs) returning strings = @{
+    for f in %xs; do echo "$f"; done | sort -u
+}
+
+#----------------------------------------------------------------------
+# File functions.
+
+# Expand a wildcard into a list of filenames.
+#
+# This function is probably not "pure" since it depends on the
+# current working directory and also files may be created in
+# the directory while goals is running which would affect the
+# result.
+function wildcard (wc) returning strings = @{
+    shopt -s nullglob
+    # Note that the substitution is quoted by goals, so to expand
+    # it we must assign it to a variable and then use it unquoted.
+    wc=%wc
+    for f in $wc; do echo "$f"; done
+}