Auto generate parser code (milvus-io#26716)

Signed-off-by: longjiquan <[email protected]>

Author: longjiquan

Diff for: internal/parser/planparserv2/README.md

@@ -11,13 +11,7 @@ The version of antlr tool: `4.9`.
 After you install the antlr4, you can generate the parser code in golang with:
 
 ```shell
-export CLASSPATH=".:${PWD}/antlr-4.9-complete.jar:$CLASSPATH"
-alias antlr4='java -Xmx500M -cp "${PWD}/antlr-4.9-complete.jar:$CLASSPATH" org.antlr.v4.Tool'
-alias grun='java -Xmx500M -cp "${PWD}/antlr-4.9-complete.jar:$CLASSPATH" org.antlr.v4.gui.TestRig'
-```
-
-```shell
-antlr4 -Dlanguage=Go -package planparserv2 -o generated -no-listener -visitor Plan.g4
+go generate
 ```
 
 All generated code will be under directory `generated`.

Diff for: internal/parser/planparserv2/generate.go

@@ -0,0 +1,3 @@
+package planparserv2
+
+//go:generate ./generate.sh

Diff for: internal/parser/planparserv2/generate.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+
+alias antlr4='java -Xmx500M -cp "../../../scripts/antlr-4.9-complete.jar:$CLASSPATH" org.antlr.v4.Tool'
+rm -fr generated
+antlr4 -Dlanguage=Go -package planparserv2 -o generated -no-listener -visitor Plan.g4