Commit 86abfb4

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Fix expressions with multiple operators. (#12)

* Fix expressions with multiple operators. Expressions such as ``1 +2;`` or ``300*200`` work, but expressions which have multiple operations do not work. For example: ``1+2+3+4`` does not work, and has to be put in a chain of parentheses to get it to work. The other valid expressions are getting evaluated to the value of the first operator, for instance, ``1*2*3`` becomes 2, by evaluating 1*2 and so on. This can be solved by adding a loop, converting the first two expressions into ``lhs`` and continuing until there are no more ``pair``s. * Added tests * Fixed test Fixed mistake in making assertion of ``1 +たす 2 +たす3 =わ=わ 2+たす2+たす3`` * Style correction. * Update parser.rs Yet another attempt to make rustfmt happy.

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calculator/src
- parser.rs

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`‎calculator/src/parser.rs`

Lines changed: 31 additions & 4 deletions

Original file line number	Diff line number	Diff line change
`@@ -36,11 +36,22 @@ fn build_ast_from_expr(pair: pest::iterators::Pair<Rule>) -> Node {`
`36`	`36`	`Rule::BinaryExpr => {`
`37`	`37`	`let mut pair = pair.into_inner();`
`38`	`38`	`let lhspair = pair.next().unwrap();`
`39`		`- let lhs = build_ast_from_term(lhspair);`
`40`		`- let op = pair.next().unwrap();`
	`39`	`+ let mutlhs = build_ast_from_term(lhspair);`
	`40`	`+ let mutop = pair.next().unwrap();`
`41`	`41`	`let rhspair = pair.next().unwrap();`
`42`		`- let rhs = build_ast_from_term(rhspair);`
`43`		`- parse_binary_expr(op, lhs, rhs)`
	`42`	`+ let mut rhs = build_ast_from_term(rhspair);`
	`43`	`+ let mut retval = parse_binary_expr(op, lhs, rhs);`
	`44`	`+ loop {`
	`45`	`+ let pair_buf = pair.next();`
	`46`	`+ if pair_buf != None {`
	`47`	`+ op = pair_buf.unwrap();`
	`48`	`+ lhs = retval;`
	`49`	`+ rhs = build_ast_from_term(pair.next().unwrap());`
	`50`	`+ retval = parse_binary_expr(op, lhs, rhs);`
	`51`	`+ } else {`
	`52`	`+ return retval;`
	`53`	`+ }`
	`54`	`+ }`
`44`	`55`	`}`
`45`	`56`	`unknown => panic!("Unknown expr: {:?}", unknown),`
`46`	`57`	`}`
`@@ -163,4 +174,20 @@ mod tests {`
`163`	`174`	`test_expr("1 + 2 + 3 + 4", "1 + (2 + (3 + 4))");`
`164`	`175`	`test_expr("1 + 2 + 3 - 4", "(1 + 2) + (3 - 4)");`
`165`	`176`	`}`
	`177`	`+`
	`178`	`+ #[test]`
	`179`	`+ fn multiple_operators() {`
	`180`	`+ assert_eq!(`
	`181`	`+ parse("1+2+3").unwrap(),`
	`182`	`+ vec![Node::BinaryExpr {`
	`183`	`+ op: Operator::Plus,`
	`184`	`+ lhs: Box::new(Node::BinaryExpr {`
	`185`	`+ op: Operator::Plus,`
	`186`	`+ lhs: Box::new(Node::Int(1)),`
	`187`	`+ rhs: Box::new(Node::Int(2)),`
	`188`	`+ }),`
	`189`	`+ rhs: Box::new(Node::Int(3)),`
	`190`	`+ }]`
	`191`	`+ )`
	`192`	`+ }`
`166`	`193`	`}`

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Commit 86abfb4

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`‎calculator/src/parser.rs`

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