英文:
How to do the parse step in ANTL4
问题
我已经根据 lexer.g4 和 parser.g4 文件生成了相关的 Java 类。
class Visitor : PostgreSQLParserBaseVisitor<Unit>() {
override fun visitSelect_stmt(ctx: PostgreSQLParser.Select_stmtContext?) {
println(ctx?.text)
super.visitSelect_stmt(ctx)
}
}
object Scratch {
@JvmStatic
fun main(args: Array<String>) {
val sql = """
SELECT * FROM table WHERE column = 1
""".trimIndent()
val lexer = PostgreSQLLexer(CharStreams.fromString(sql))
val parser = PostgreSQLParser(CommonTokenStream(lexer))
val parseTree: ParseTree = parser.??? <<<
Visitor().visit(parseTree)
}
}
英文:
I've generated the relevant Java classes given a lexer.g4 and parser.g4 file
I've written a visitor, but in order to use the Visitor, i need an actual parse tree, how do i get the parse tree from the parser?
In other online examples, there's mention of parser.parse() but that doesn't compile under ANTLR4
class Visitor : PostgreSQLParserBaseVisitor<Unit>() {
override fun visitSelect_stmt(ctx: PostgreSQLParser.Select_stmtContext?) {
println(ctx?.text)
super.visitSelect_stmt(ctx)
}
}
object Scratch {
@JvmStatic
fun main(args: Array<String>) {
val sql = """
SELECT * FROM table WHERE column = 1
""".trimIndent()
val lexer = PostgreSQLLexer(CharStreams.fromString(sql))
val parser = PostgreSQLParser(CommonTokenStream(lexer))
val parseTree: ParseTree = parser.??? <<<
Visitor().visit(parseTree)
}
}
答案1
得分: 1
parse() 方法对应于名为 parse 的解析器规则。如果您正在使用 这个 PostgreSQL 语法，您可能会想使用属于语法入口规则的 root() 方法：
root
: stmt ((SEMI stmt)+ SEMI)? EOF
;
英文:
The parse() method corresponds to a parser rule called parse. If this is the PostgreSQL grammar you're using, you'll probably want to use the root() method belonging to the entry rule of the grammar:
root
: stmt ((SEMI stmt)+ SEMI)? EOF
;
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论