joepie91/pegjs
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

Update arithmetics example (Value plucking)

Browse source
This commit is contained in:
Futago-za Ryuu 2018-09-18 07:27:21 +01:00
parent e0e9fbcd30
commit fd3dbb77ac
1 changed files with 9 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
examples/arithmetics.pegjs
View file

@ -4,23 +4,23 @@
// Accepts expressions like "2 * (3 + 4)" and computes their value.
Expression
= head:Term tail:(_ ("+" / "-") _ Term)* {
return tail.reduce(function(result, element) {
if (element[1] === "+") { return result + element[3]; }
if (element[1] === "-") { return result - element[3]; }
= head:Term tail:(_ @("+" / "-") _ @Term)* {
return tail.reduce(function(result, [operator, factor]) {
if (operator === "+") return result + factor;
if (operator === "-") return result - factor;
}, head);
}
Term
= head:Factor tail:(_ ("*" / "/") _ Factor)* {
return tail.reduce(function(result, element) {
if (element[1] === "*") { return result * element[3]; }
if (element[1] === "/") { return result / element[3]; }
= head:Factor tail:(_ @("*" / "/") _ @Factor)* {
return tail.reduce(function(result, [operator, factor]) {
if (operator === "*") return result * factor;
if (operator === "/") return result / factor;
}, head);
}
Factor
= "(" _ expr:Expression _ ")" { return expr; }
= "(" _ @Expression _ ")"
/ Integer
Integer "integer"