Add Y and Z registers

4 files changed, 39 insertions, 3 deletions

diff --git a/README.md b/README.md
index 032a71d..668e645 100644
--- a/README.md
+++ b/README.md
@@ -18,9 +18,9 @@ I'm hoping it will be capable of nearly as much as jq, with comparable or better
 ## Usage
 
 ### Registers and Atoms
-Commands operate on data that is store in 'registers'. There are 3 registers: path, value and X.
+Commands operate on data that is store in 'registers'. There are 5 registers: path, value, X, Y and Z.
 
-The path register stores the global path from the root node to the current token, the value register stores the token itself and the X register is a general purpose register, good for keeping things for later.
+The path register stores the global path from the root node to the current token, the value register stores the token itself and the X, Y and Z registers are general purpose registers, good for keeping things for later.
 
 With the following JSON being read:
 ```
@@ -162,5 +162,9 @@ With an understanding of subexes, we can look at the stred commands
 | `o` | Do nothing |
 | `x` | Swap the value register with the X register |
 | `X` | Append the contents of the value register to the X register |
+| `y` | Swap the value register with the Y register |
+| `Y` | Append the contents of the value register to the Y register |
+| `z` | Swap the value register with the Z register |
+| `Z` | Append the contents of the value register to the Z register |
 | `k` | Swap the value register with the path register |
 | `K` | Append the contents of the value register to the path register |
diff --git a/main/command.go b/main/command.go
index 9403020..296ad69 100644
--- a/main/command.go
+++ b/main/command.go
@@ -107,6 +107,30 @@ func (cmd AppendXRegCommand) exec(state *ProgramState) {
 	state.xreg = append(state.xreg, state.value...)
 }
 
+type SwapYRegCommand struct {}
+func (cmd SwapYRegCommand) exec(state *ProgramState) {
+	v := state.value
+	state.value = state.yreg
+	state.yreg = v
+}
+
+type AppendYRegCommand struct {}
+func (cmd AppendYRegCommand) exec(state *ProgramState) {
+	state.yreg = append(state.yreg, state.value...)
+}
+
+type SwapZRegCommand struct {}
+func (cmd SwapZRegCommand) exec(state *ProgramState) {
+	v := state.value
+	state.value = state.zreg
+	state.zreg = v
+}
+
+type AppendZRegCommand struct {}
+func (cmd AppendZRegCommand) exec(state *ProgramState) {
+	state.zreg = append(state.zreg, state.value...)
+}
+
 type SwapPathCommand struct {}
 func (cmd SwapPathCommand) exec(state *ProgramState) {
 	v := state.value
diff --git a/main/main.go b/main/main.go
index 0c7324b..2067920 100644
--- a/main/main.go
+++ b/main/main.go
@@ -9,7 +9,7 @@ import (
 type Program []Command
 
 type ProgramState struct {
-	path, value, xreg []walk.Atom
+	path, value, xreg, yreg, zreg []walk.Atom
 	in walk.JSONIn
 	out walk.JSONOut
 	program []Command
diff --git a/main/parse.go b/main/parse.go
index d31687a..1972b66 100644
--- a/main/parse.go
+++ b/main/parse.go
@@ -142,6 +142,14 @@ func (p *parser) parseBasicCommand(commandChar rune) Command {
 			return SwapXRegCommand{}
 		case 'X':
 			return AppendXRegCommand{}
+		case 'y':
+			return SwapYRegCommand{}
+		case 'Y':
+			return AppendYRegCommand{}
+		case 'z':
+			return SwapZRegCommand{}
+		case 'Z':
+			return AppendZRegCommand{}
 		case 'k':
 			return SwapPathCommand{}
 		case 'K':