stdlib: Fix %branch -> %fedora-branch.

[goals.git] / stdlib / prelude.gl

diff --git a/stdlib/prelude.gl b/stdlib/prelude.gl
index d496d71..836b5c4 100644 (file)
--- a/stdlib/prelude.gl
+++ b/stdlib/prelude.gl
@@ -40,6 +40,11 @@ tactic *exists (filename) = @{
 #----------------------------------------------------------------------
 # Basic functions.
 
+function error (msg) = @{
+    echo %msg >&2
+    exit 1
+}
+
 # Wrap list of strings in a call or tactic.
 pure function wrap (wrapper, xs) = @{
     echo '['
@@ -54,11 +59,60 @@ pure function wrap (wrapper, xs) = @{
 #----------------------------------------------------------------------
 # Text functions.
 
+# Filter a list by regexp.
+pure function filter (pat, xs) returning strings = @{
+    for f in %xs; do echo "$f"; done | grep -E -- %pat
+}
+
+# Filter out a list by regexp.
+pure function filter-out (pat, xs) returning strings = @{
+    for f in %xs; do echo "$f"; done | grep -v -E -- %pat
+}
+
+# Head of a list.
+pure function head (xs) returning string = @{
+    for f in %xs; do
+        echo "$f"
+        exit 0
+    done
+}
+
+# Join two lists.
+pure function join (xs, ys) returning strings = @{
+    for f in %xs %ys; do echo "$f"; done
+}
+
+# Last element of a list.
+pure function last (xs) returning string = @{
+    for f in %xs; do
+        r="$f"
+    done
+    echo "$r"
+}
+
+# n'th element of a list.
+pure function nth (n, xs) returning string = @{
+    i=0
+    r=
+    for f in %xs; do
+        if [ $i -eq %n ]; then r="$f"; fi
+        ((++i))
+    done
+    echo "$r"
+}
+
 # Sort + uniq a list.
 pure function sort (xs) returning strings = @{
     for f in %xs; do echo "$f"; done | sort -u
 }
 
+# Split a string into a list.
+# https://superuser.com/a/1066541
+pure function split (s) returning strings = @{
+    s=%s
+    eval 'for f in '$s'; do echo "$f"; done'
+}
+
 # Substitute.
 pure function subst (from, to, text) returning string = @{
     # We need to replace any / characters in ‘to’ with escaped ones.
@@ -66,17 +120,26 @@ pure function subst (from, to, text) returning string = @{
     echo %text | sed -E s/%from/$to/g
 }
 
+# Tail of a list.
+pure function tail (xs) returning strings = @{
+    drop=1
+    for f in %xs; do
+        if [ -z "$drop" ]; then echo "$f"; fi
+        drop=
+    done
+}
+
 #----------------------------------------------------------------------
 # File functions.
 
 # Base name.
 pure function basename (name) returning string = @{
-    basename %name
+    basename -- %name
 }
 
 # Directory name.
 pure function dirname (name) returning string = @{
-    dirname %name
+    dirname -- %name
 }
 
 # File extension.
@@ -85,6 +148,21 @@ pure function extension (name) returning string = @{
     echo "${name##*.}"
 }
 
+# Read a file.
+function read (filename) returning string = @{
+    cat -- %filename
+}
+
+# Read a file as a list of lines.
+function readlines (filename) returning strings = @{
+    cat -- %filename
+}
+
+# Real path.
+function realpath (filename) returning string = @{
+    realpath -- %filename
+}
+
 # Expand a wildcard into a list of filenames.
 #
 # This function is probably not "pure" since it depends on the