Add get support for dicts

dict.go

@@ -5,6 +5,13 @@ import (
 	"github.com/mitchellh/copystructure"
 )
 
+func get(d map[string]interface{}, key string) interface{} {
+	if val, ok := d[key]; ok {
+		return val
+	}
+	return ""
+}
+
 func set(d map[string]interface{}, key string, value interface{}) map[string]interface{} {
 	d[key] = value
 	return d

dict_test.go

@@ -111,6 +111,19 @@ func TestOmit(t *testing.T) {
 	}
 }
 
+func TestGet(t *testing.T) {
+	tests := map[string]string{
+		`{{- $d := dict "one" 1 }}{{ get $d "one"  -}}`:          "1",
+		`{{- $d := dict "one" 1 "two" "2" }}{{ get $d "two" -}}`: "2",
+		`{{- $d := dict }}{{ get $d "two" -}}`:                   "",
+	}
+	for tpl, expect := range tests {
+		if err := runt(tpl, expect); err != nil {
+			t.Error(err)
+		}
+	}
+}
+
 func TestSet(t *testing.T) {
 	tpl := `{{- $d := dict "one" 1 "two" 222222 -}}
 	{{- $_ := set $d "two" 2 -}}

docs/dicts.md

@@ -20,6 +20,19 @@ The following creates a dictionary with three items:
 $myDict := dict "name1" "value1" "name2" "value2" "name3" "value 3"
 ```
 
+## get
+
+Given a map and a key, get the value from the map.
+
+```
+get $myDict "key1"
+```
+
+The above returns `"value1"`
+
+Note that if the key is not found, this operation will simply return `""`. No error
+will be generated.
+
 ## set
 
 Use `set` to add a new key/value pair to a dictionary.

functions.go

@@ -256,6 +256,7 @@ var genericMap = map[string]interface{}{
 	"tuple":              list, // FIXME: with the addition of append/prepend these are no longer immutable.
 	"list":               list,
 	"dict":               dict,
+	"get":                get,
 	"set":                set,
 	"unset":              unset,
 	"hasKey":             hasKey,