From cf75e9e7b8195ef7b02d4dde4609d30a2ab255fe Mon Sep 17 00:00:00 2001
From: Florian Limberger <flo@purplekraken.com>
Date: Thu, 23 Apr 2020 12:36:47 +0200
Subject: [PATCH] Implement variable expansion in includes

Signed-off-by: Florian Limberger <flo@purplekraken.com>
---
 mk.go    |  8 +++++++-
 parse.go | 16 +++++++++++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/mk.go b/mk.go
index 915429a..e238ad5 100644
--- a/mk.go
+++ b/mk.go
@@ -328,7 +328,13 @@ func main() {
 		mkError("unable to find mkfile's absolute path")
 	}
 
-	rs := parse(string(input), mkfilepath, abspath)
+	env := make(map[string][]string)
+	for _, elem := range os.Environ() {
+		vals := strings.SplitN(elem, "=", 2)
+		env[vals[0]] = append(env[vals[0]], vals[1])
+	}
+
+	rs := parse(string(input), mkfilepath, abspath, env)
 	if quiet {
 		for i := range rs.rules {
 			rs.rules[i].attributes.quiet = true
diff --git a/parse.go b/parse.go
index 4e76540..04d6b48 100644
--- a/parse.go
+++ b/parse.go
@@ -52,8 +52,8 @@ func (p *parser) clear() {
 type parserStateFun func(*parser, token) parserStateFun
 
 // Parse a mkfile, returning a new ruleSet.
-func parse(input string, name string, path string) *ruleSet {
-	rules := &ruleSet{make(map[string][]string),
+func parse(input string, name string, path string, env map[string][]string) *ruleSet {
+	rules := &ruleSet{env,
 		make([]rule, 0),
 		make(map[string][]int)}
 	parseInto(input, name, rules, path)
@@ -115,7 +115,12 @@ func parsePipeInclude(p *parser, t token) parserStateFun {
 
 		args := make([]string, len(p.tokenbuf))
 		for i := 0; i < len(p.tokenbuf); i++ {
-			args[i] = p.tokenbuf[i].val
+			s := p.tokenbuf[i].val
+			expanded := expand(s, p.rules.vars, false)
+			if len(expanded) > 0 {
+				s = expanded[0]
+			}
+			args[i] = s
 		}
 
 		output, success := subprocess("sh", args, "", true)
@@ -155,6 +160,11 @@ func parseRedirInclude(p *parser, t token) parserStateFun {
 		for i := range p.tokenbuf {
 			filename += p.tokenbuf[i].val
 		}
+		expanded := expand(filename, p.rules.vars, false)
+		if len(expanded) > 0 {
+			filename = expanded[0]
+		}
+		fmt.Printf("parsed filename: %v\nexpanded filename: %v\n", filename, expanded)
 		file, err := os.Open(filename)
 		if err != nil {
 			p.basicErrorAtToken(fmt.Sprintf("cannot open %s", filename), p.tokenbuf[0])