From 34bc33d5c5b5ea4da4ba31715f2dfaa3f62fd7dd Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Sat, 9 Jan 2021 11:33:39 +1100
Subject: [PATCH] strenv

---
 pkg/yqlib/doc/Env Variable Operators.md | 21 +++++++++++++++++++++
 pkg/yqlib/lib.go                        |  1 +
 pkg/yqlib/operator_env_test.go          |  2 +-
 pkg/yqlib/operators_test.go             | 20 +++++++++++++++++---
 pkg/yqlib/path_tokeniser.go             | 20 ++++++++++++++++++++
 5 files changed, 60 insertions(+), 4 deletions(-)
 create mode 100644 pkg/yqlib/doc/Env Variable Operators.md

diff --git a/pkg/yqlib/doc/Env Variable Operators.md b/pkg/yqlib/doc/Env Variable Operators.md
new file mode 100644
index 00000000..6f69515a
--- /dev/null
+++ b/pkg/yqlib/doc/Env Variable Operators.md	
@@ -0,0 +1,21 @@
+
+## Read boolean environment variable as a string
+Running
+```bash
+myenv="true" yq eval --null-input 'strenv(myenv)'
+```
+will output
+```yaml
+12
+```
+
+## Read numeric environment variable as a string
+Running
+```bash
+myenv="12" yq eval --null-input 'strenv(myenv)'
+```
+will output
+```yaml
+12
+```
+
diff --git a/pkg/yqlib/lib.go b/pkg/yqlib/lib.go
index fbe69dd0..db8402f3 100644
--- a/pkg/yqlib/lib.go
+++ b/pkg/yqlib/lib.go
@@ -70,6 +70,7 @@ var TraverseArray = &OperationType{Type: "TRAVERSE_ARRAY", NumArgs: 1, Precedenc
 var DocumentFilter = &OperationType{Type: "DOCUMENT_FILTER", NumArgs: 0, Precedence: 50, Handler: TraversePathOperator}
 var SelfReference = &OperationType{Type: "SELF", NumArgs: 0, Precedence: 50, Handler: SelfOperator}
 var ValueOp = &OperationType{Type: "VALUE", NumArgs: 0, Precedence: 50, Handler: ValueOperator}
+var EnvOp = &OperationType{Type: "ENV", NumArgs: 0, Precedence: 50, Handler: EnvOperator}
 var Not = &OperationType{Type: "NOT", NumArgs: 0, Precedence: 50, Handler: NotOperator}
 var Empty = &OperationType{Type: "EMPTY", NumArgs: 50, Handler: EmptyOperator}
 
diff --git a/pkg/yqlib/operator_env_test.go b/pkg/yqlib/operator_env_test.go
index d70cef32..0569e38e 100644
--- a/pkg/yqlib/operator_env_test.go
+++ b/pkg/yqlib/operator_env_test.go
@@ -27,5 +27,5 @@ func TestEnvOperatorScenarios(t *testing.T) {
 	for _, tt := range envOperatorScenarios {
 		testScenario(t, &tt)
 	}
-	documentScenarios(t, "Env Variable Operators", addOperatorScenarios)
+	documentScenarios(t, "Env Variable Operators", envOperatorScenarios)
 }
diff --git a/pkg/yqlib/operators_test.go b/pkg/yqlib/operators_test.go
index c8881bb5..5064410f 100644
--- a/pkg/yqlib/operators_test.go
+++ b/pkg/yqlib/operators_test.go
@@ -17,6 +17,7 @@ import (
 type expressionScenario struct {
 	description           string
 	subdescription        string
+	environmentVariable	string
 	document              string
 	document2             string
 	expression            string
@@ -61,6 +62,10 @@ func testScenario(t *testing.T, s *expressionScenario) {
 
 	}
 
+	if s.environmentVariable != "" {
+		os.Setenv("myenv", s.environmentVariable)
+	}
+
 	results, err = treeNavigator.GetMatchingNodes(inputs, node)
 
 	if err != nil {
@@ -162,6 +167,13 @@ func documentInput(w *bufio.Writer, s expressionScenario) (string, string) {
 	formattedDoc := ""
 	formattedDoc2 := ""
 	command := "eval"
+
+	envCommand := ""
+
+		if(s.environmentVariable != "") {
+			envCommand = fmt.Sprintf("myenv=\"%v\" ", s.environmentVariable)
+		}
+		
 	if s.document != "" {
 		if s.dontFormatInputForDoc {
 			formattedDoc = s.document + "\n"
@@ -188,14 +200,16 @@ func documentInput(w *bufio.Writer, s expressionScenario) (string, string) {
 		}
 
 		writeOrPanic(w, "then\n")
+		
+
 		if s.expression != "" {
-			writeOrPanic(w, fmt.Sprintf("```bash\nyq %v '%v' %v\n```\n", command, s.expression, files))
+			writeOrPanic(w, fmt.Sprintf("```bash\n%vyq %v '%v' %v\n```\n", envCommand, command, s.expression, files))
 		} else {
-			writeOrPanic(w, fmt.Sprintf("```bash\nyq %v %v\n```\n", command, files))
+			writeOrPanic(w, fmt.Sprintf("```bash\n%vyq %v %v\n```\n", envCommand, command, files))
 		}
 	} else {
 		writeOrPanic(w, "Running\n")
-		writeOrPanic(w, fmt.Sprintf("```bash\nyq %v --null-input '%v'\n```\n", command, s.expression))
+		writeOrPanic(w, fmt.Sprintf("```bash\n%vyq %v --null-input '%v'\n```\n", envCommand, command, s.expression))
 	}
 	return formattedDoc, formattedDoc2
 }
diff --git a/pkg/yqlib/path_tokeniser.go b/pkg/yqlib/path_tokeniser.go
index 6afac412..20f77fdd 100644
--- a/pkg/yqlib/path_tokeniser.go
+++ b/pkg/yqlib/path_tokeniser.go
@@ -178,6 +178,25 @@ func stringValue(wrapped bool) lex.Action {
 	}
 }
 
+func envOp(strenv bool) lex.Action {
+	return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
+		value := string(m.Bytes)
+
+		if strenv {
+			// strenv( )
+			value = value[7:len(value)-1]
+		 } else {
+			//env( )
+			value = value[4:len(value)-1]
+		 }
+
+		envOperation := CreateValueOperation(value, value)
+		envOperation.OperationType = EnvOp
+
+		return &Token{TokenType: OperationToken, Operation: envOperation}, nil
+	}
+}
+
 func nullValue() lex.Action {
 	return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
 		return &Token{TokenType: OperationToken, Operation: CreateValueOperation(nil, string(m.Bytes))}, nil
@@ -266,6 +285,7 @@ func initLexer() (*lex.Lexer, error) {
 	lexer.Add([]byte(`~`), nullValue())
 
 	lexer.Add([]byte(`"[^"]*"`), stringValue(true))
+	lexer.Add([]byte(`strenv\([^\)]+\)`), envOp(true))
 
 	lexer.Add([]byte(`\[`), literalToken(OpenCollect, false))
 	lexer.Add([]byte(`\]`), literalToken(CloseCollect, true))