Add upper and lowercase expression functions

docs/usage/expressions.md

@@ -184,6 +184,12 @@ Syntax: `{substr {0} pos length}`
 
 Takes the substring of the first argument starting at `pos` for `length`
 
+### Upper, Lower
+
+Syntax: `{upper val}`, `{lower val}`
+
+Converts a string to all-upper or all-lower case
+
 ### Repeat
 
 Syntax: `{repeat "string" {numtimes}}`

pkg/expressions/stdlib/funcs.go

@@ -1,6 +1,8 @@
 package stdlib
 
-import . "rare/pkg/expressions" //lint:ignore ST1001 Legacy
+import (
+	. "rare/pkg/expressions" //lint:ignore ST1001 Legacy
+)
 
 var StandardFunctions = map[string]KeyBuilderFunction{
 	"coalesce":  KeyBuilderFunction(kfCoalesce),
@@ -52,6 +54,8 @@ var StandardFunctions = map[string]KeyBuilderFunction{
 	"format": KeyBuilderFunction(kfFormat),
 	"substr": KeyBuilderFunction(kfSubstr),
 	"select": KeyBuilderFunction(kfSelect),
+	"upper":  KeyBuilderFunction(kfUpper),
+	"lower":  KeyBuilderFunction(kfLower),
 
 	// Separation (Join)
 	"tab": kfJoin('\t'),

pkg/expressions/stdlib/funcsStrings.go

@@ -41,6 +41,24 @@ func kfSuffix(args []KeyBuilderStage) KeyBuilderStage {
 	})
 }
 
+func kfUpper(args []KeyBuilderStage) KeyBuilderStage {
+	if len(args) != 1 {
+		return stageLiteral(ErrorArgCount)
+	}
+	return func(context KeyBuilderContext) string {
+		return strings.ToUpper(args[0](context))
+	}
+}
+
+func kfLower(args []KeyBuilderStage) KeyBuilderStage {
+	if len(args) != 1 {
+		return stageLiteral(ErrorArgCount)
+	}
+	return func(context KeyBuilderContext) string {
+		return strings.ToLower(args[0](context))
+	}
+}
+
 // {substr {0} }
 func kfSubstr(args []KeyBuilderStage) KeyBuilderStage {
 	if len(args) != 3 {

pkg/expressions/stdlib/funcsStrings_test.go

@@ -7,6 +7,11 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestUpperLower(t *testing.T) {
+	testExpression(t, mockContext("aBc"), "{upper {0}} {upper a b}", "ABC <ARGN>")
+	testExpression(t, mockContext("aBc"), "{lower {0}} {lower a b}", "abc <ARGN>")
+}
+
 func TestSubstring(t *testing.T) {
 	testExpression(t,
 		mockContext("abcd"),