1 files changed, 50 insertions, 6 deletions
diff --git a/main/parse.go b/main/parse.go
index 9c7a437..3e0e80b 100644
--- a/main/parse.go
+++ b/main/parse.go
@@ -76,17 +76,61 @@ func (p *parser) parseBasicCommand(commands []Command, commandChar rune) []Comma
 		case 'o':
 			return append(commands, NoopCommand{})
 		case 'x':
-			return append(commands, SwapXRegCommand{})
+			delim := p.peek()
+			if delim.typ != TokenSubstituteDelimiter {
+				return append(commands, SwapXRegCommand{})
+			}
+			ast := p.parseSubex()
+			subex := subex.CompileTransducer(ast)
+			return append(commands, SubstituteToXRegCommand {subex}, JumpCommand {len(commands) + 3})
 		case 'X':
-			return append(commands, AppendXRegCommand{})
+			delim := p.peek()
+			if delim.typ != TokenSubstituteDelimiter {
+				return append(commands, AppendXRegCommand{})
+			}
+			ast := p.parseSubex()
+			subex := subex.CompileTransducer(ast)
+			return append(commands, SubstituteAppendXRegCommand {subex}, JumpCommand {len(commands) + 3})
 		case 'y':
-			return append(commands, SwapYRegCommand{})
+			delim := p.peek()
+			if delim.typ != TokenSubstituteDelimiter {
+				return append(commands, SwapYRegCommand{})
+			}
+			ast := p.parseSubex()
+			subex := subex.CompileTransducer(ast)
+			return append(commands, SubstituteToYRegCommand {subex}, JumpCommand {len(commands) + 3})
 		case 'Y':
-			return append(commands, AppendYRegCommand{})
+			delim := p.peek()
+			if delim.typ != TokenSubstituteDelimiter {
+				return append(commands, AppendYRegCommand{})
+			}
+			ast := p.parseSubex()
+			subex := subex.CompileTransducer(ast)
+			return append(commands, SubstituteAppendYRegCommand {subex}, JumpCommand {len(commands) + 3})
 		case 'z':
-			return append(commands, SwapZRegCommand{})
+			delim := p.peek()
+			if delim.typ != TokenSubstituteDelimiter {
+				return append(commands, SwapZRegCommand{})
+			}
+			ast := p.parseSubex()
+			subex := subex.CompileTransducer(ast)
+			return append(commands, SubstituteToZRegCommand {subex}, JumpCommand {len(commands) + 3})
 		case 'Z':
-			return append(commands, AppendZRegCommand{})
+			delim := p.peek()
+			if delim.typ != TokenSubstituteDelimiter {
+				return append(commands, AppendZRegCommand{})
+			}
+			ast := p.parseSubex()
+			subex := subex.CompileTransducer(ast)
+			return append(commands, SubstituteAppendZRegCommand {subex}, JumpCommand {len(commands) + 3})
+		case 'a':
+			return append(commands, IsStartCommand{}, JumpCommand {len(commands) + 3})
+		case 'A':
+			return append(commands, IsPrevStartCommand{}, JumpCommand {len(commands) + 3})
+		case 'e':
+			return append(commands, IsEndCommand{}, JumpCommand {len(commands) + 3})
+		case 'E':
+			return append(commands, IsNextEndCommand{}, JumpCommand {len(commands) + 3})
 		case ':':
 			labelToken := p.next()
 			if labelToken.typ != TokenLabel {