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mikrotik-java
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Cleanup to parser

This commit is contained in:
Gideon Le Grange 2020-01-03 08:52:01 +02:00
parent 7d29f9265e
commit 1f31a6f3b5
1 changed files with 41 additions and 28 deletions
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69
src/main/java/me/legrange/mikrotik/impl/Parser.java
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@ -3,24 +3,30 @@ package me.legrange.mikrotik.impl;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import me.legrange.mikrotik.impl.Scanner.Token;
/**
* Parse the pseudo-command line into command objects.
* Parse the pseudo-command line into command objects.
*
* @author GideonLeGrange
*/
class Parser {
/** parse the given bit of text into a Command object */
/**
* parse the given bit of text into a Command object
*/
static Command parse(String text) throws ParseException {
Parser parser = new Parser(text);
return parser.parse();
}
/** run parse on the internal data and return the command object */
/**
* run parse on the internal data and return the command object
*/
private Command parse() throws ParseException {
command();
while (!is(Token.WHERE, Token.RETURN, Token.EOL)) {
while (!is(Token.WHERE, Token.RETURN, Token.EOL)) {
param();
}
if (token == Token.WHERE) {
@ -32,7 +38,7 @@ class Parser {
expect(Token.EOL);
return cmd;
}
private void command() throws ParseException {
StringBuilder path = new StringBuilder();
do {
@ -67,8 +73,7 @@ class Parser {
next();
}
cmd.addParameter(new Parameter(name, val.toString()));
}
else {
} else {
cmd.addParameter(new Parameter(name));
}
}
@ -92,7 +97,7 @@ class Parser {
case EQUALS:
eqExpr(name);
break;
case NOT_EQUALS :
case NOT_EQUALS:
notExpr(name);
break;
case LESS:
@ -106,30 +111,36 @@ class Parser {
}
}
break;
case LEFT_BRACKET : {
next();
expr();
expect(Token.RIGHT_BRACKET);
next();
}
break;
case LEFT_BRACKET:
nestedExpr();
break;
}
// if you get here, you had a expression, see if you want more.
switch (token) {
case AND : andExpr();
case AND:
andExpr();
break;
case OR : orExpr();
case OR:
orExpr();
break;
}
}
private void nestedExpr() throws ParseException {
expect(Token.LEFT_BRACKET);
next();
expr();
expect(Token.RIGHT_BRACKET);
next();
}
private void andExpr() throws ParseException {
next(); // eat and
expr();
cmd.addQuery("?#&");
}
private void orExpr() throws ParseException {
private void orExpr() throws ParseException {
next(); // eat or
expr();
cmd.addQuery("?#|");
@ -142,7 +153,7 @@ class Parser {
cmd.addQuery("?#!");
}
private void eqExpr(String name) throws ParseException {
private void eqExpr(String name) throws ParseException {
next(); // eat =
expect(Token.TEXT);
cmd.addQuery(String.format("?%s=%s", name, text));
@ -161,7 +172,7 @@ class Parser {
cmd.addQuery("?#!");
next();
}
private void moreExpr(String name) throws ScanException {
next(); // eat >
cmd.addQuery(String.format("?>%s=%s", name, text));
@ -185,19 +196,21 @@ class Parser {
cmd.addProperty(props.toArray(new String[props.size()]));
}
private void expect(Token...tokens) throws ParseException {
if (!is(tokens))
private void expect(Token... tokens) throws ParseException {
if (!is(tokens))
throw new ParseException(String.format("Expected %s but found %s at position %d", Arrays.asList(tokens), this.token, scanner.pos()));
}
private boolean is(Token...tokens) {
private boolean is(Token... tokens) {
for (Token want : tokens) {
if (this.token == want) return true;
}
return false;
}
/** move to the next token returned by the scanner */
/**
* move to the next token returned by the scanner
*/
private void next() throws ScanException {
token = scanner.next();
while (token == Token.WS) {
@ -211,7 +224,7 @@ class Parser {
scanner = new Scanner(line);
next();
}
private final Scanner scanner;
private Token token;
private String text;