From c50170f000d382fa02090fbf79d0e5d12036f53b Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Mon, 5 Apr 2021 11:41:17 -0600
Subject: implement function `realpath`

---
 src/makefile/functions.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/makefile/functions.rs b/src/makefile/functions.rs
index 6dacd10..6815ac4 100644
--- a/src/makefile/functions.rs
+++ b/src/makefile/functions.rs
@@ -53,6 +53,10 @@ pub fn expand_call(
             assert_eq!(args.len(), 1);
             file_name::wildcard(macros, &args[0])
         }
+        "realpath" => {
+            assert_eq!(args.len(), 1);
+            file_name::realpath(macros, &args[0])
+        }
 
         "if" => {
             assert!(args.len() == 2 || args.len() == 3);
@@ -179,6 +183,7 @@ mod text {
 mod file_name {
     use std::env;
     use std::ffi::OsStr;
+    use std::fs;
     use std::path::Path;
 
     use eyre::WrapErr;
@@ -246,6 +251,19 @@ mod file_name {
             .collect::<Vec<_>>();
         Ok(results.join(" "))
     }
+
+    pub fn realpath(macros: &MacroSet, targets: &TokenString) -> Result<String> {
+        let targets = macros.expand(targets)?;
+        let results = targets
+            .split_whitespace()
+            .map(|x| {
+                fs::canonicalize(x)
+                    .map(|p| p.to_string_lossy().into_owned())
+                    .unwrap_or_else(|_| x.to_owned())
+            })
+            .collect::<Vec<_>>();
+        Ok(results.join(" "))
+    }
 }
 
 // Functions for Conditionals
-- 
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