stdlib: Implement read() and readlines() functions.

[goals.git] / stdlib / prelude.gl

diff --git a/stdlib/prelude.gl b/stdlib/prelude.gl
index a73ef1a..5d072ea 100644 (file)
--- a/stdlib/prelude.gl
+++ b/stdlib/prelude.gl
@@ -54,14 +54,74 @@ pure function wrap (wrapper, xs) = @{
 #----------------------------------------------------------------------
 # Text functions.
 
+# 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
+}
+
 # Sort + uniq a list.
 pure function sort (xs) returning strings = @{
     for f in %xs; do echo "$f"; done | sort -u
 }
 
+# Substitute.
+pure function subst (from, to, text) returning string = @{
+    # We need to replace any / characters in ‘to’ with escaped ones.
+    to="$( echo -n %to | sed 's,/,\\/,g' )"
+    echo %text | sed -E s/%from/$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
+}
+
+# Directory name.
+pure function dirname (name) returning string = @{
+    dirname %name
+}
+
+# File extension.
+pure function extension (name) returning string = @{
+    name=%name
+    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