parse

Author: masx200

basic-calculator-iv/parse.ts

@@ -1,5 +1,65 @@
 import { Poly } from "./Poly.ts";
+/**  我们依然使用递归下降法来解决这个问题，文法如下：
 
+exp :=( exp "+"||"-" additive) || additive
+
+additive := (additive "*" factor) || additive
+
+factor := num || "("exp")" || variable(变量)
+ */
 export function parse(tokens: (string | number)[]): Poly {
-    throw new Error("Function not implemented.");
+    let index = 0;
+    // console.log(tokens);
+    function expression(): Poly {
+        let res = additive();
+        while (
+            index < tokens.length &&
+            (tokens[index] == "+" || tokens[index] == "-")
+        ) {
+            const op = tokens[index];
+            index++;
+            const temp = additive();
+            // console.log(op);
+            if (op == "+") {
+                res = res.add(temp);
+            } else {
+                res = res.sub(temp);
+            }
+        }
+        // console.log("expression", [...res]);
+        return res;
+    }
+    function additive(): Poly {
+        let res = factor();
+        while (index < tokens.length && tokens[index] == "*") {
+            // console.log(tokens[index]);
+            index++;
+            const fac = factor();
+            res = res.mul(fac);
+        }
+        // console.log("additive", [...res]);
+        return res;
+    }
+    function factor(): Poly {
+        let res = new Poly();
+        if (index < tokens.length && tokens[index] == "(") {
+            // console.log(tokens[index]);
+            index++;
+            res = expression();
+            // console.log(tokens[index]);
+            index++;
+        } else if (index < tokens.length) {
+            if (typeof tokens[index] === "number") {
+                const num = Number(tokens[index]);
+                res = res.add(new Poly([[[], num]]));
+            } else {
+                const variable = String(tokens[index]);
+                res = res.add(new Poly([[[variable], 1]]));
+            }
+            index++;
+        }
+        // console.log("factor", [...res]);
+        return res;
+    }
+    return expression();
 }

basic-calculator-iv/test.ts

@@ -1,6 +1,7 @@
 import { Poly } from "./Poly.ts";
 import { assertEquals } from "https://deno.land/[email protected]/testing/asserts.ts";
 import { tokenize } from "./tokenize.ts";
+import basicCalculatorIV from "./index.ts";
 
 Deno.test("poly", () => {
     const p1 = new Poly([
@@ -161,3 +162,55 @@ Deno.test("tokenize", () => {
         4,
     ]);
 });
+Deno.test("basic-calculator-iv", () => {
+    assertEquals(
+        basicCalculatorIV(
+            "e - 8 + temperature - pressure",
+            ["e", "temperature"],
+            [1, 12],
+        ),
+        ["-1*pressure", "5"],
+    );
+    assertEquals(basicCalculatorIV("e + 8 - a + 5", ["e"], [1]), [
+        "-1*a",
+        "14",
+    ]);
+    assertEquals(basicCalculatorIV("(e + 8) * (e - 8)", [], []), [
+        "1*e*e",
+        "-64",
+    ]);
+    assertEquals(basicCalculatorIV("a * b * c + b * a * c * 4", [], []), [
+        "5*a*b*c",
+    ]);
+    assertEquals(
+        basicCalculatorIV(
+            "((a - b) * (b - c) + (c - a)) * ((a - b) + (b - c) * (c - a))",
+            [],
+            [],
+        ),
+        [
+            "-1*a*a*b*b",
+            "2*a*a*b*c",
+            "-1*a*a*c*c",
+            "1*a*b*b*b",
+            "-1*a*b*b*c",
+            "-1*a*b*c*c",
+            "1*a*c*c*c",
+            "-1*b*b*b*c",
+            "2*b*b*c*c",
+            "-1*b*c*c*c",
+            "2*a*a*b",
+            "-2*a*a*c",
+            "-2*a*b*b",
+            "2*a*c*c",
+            "1*b*b*b",
+            "-1*b*b*c",
+            "1*b*c*c",
+            "-1*c*c*c",
+            "-1*a*a",
+            "1*a*b",
+            "1*a*c",
+            "-1*b*c",
+        ],
+    );
+});

basic-calculator/test.ts

@@ -96,13 +96,13 @@ Deno.test("Parenthesized-expression", () => {
         },
     });
 });
-Deno.test("simple-calculate", () => {
+Deno.test("basic-calculator-simple-calculate", () => {
     assertEquals(calculate("-199+5998"), -199 + 5998);
 });
-Deno.test("Parenthesized-calculate", () => {
+Deno.test("basic-calculator-Parenthesized-calculate", () => {
     assertEquals(calculate("-(-199+5998)+87"), -(-199 + 5998) + 87);
 });
-Deno.test("testcases-calculate", () => {
+Deno.test("basic-calculator-test-cases-calculate", () => {
     assertEquals(calculate("1 + 1"), 2);
     assertEquals(calculate(" 2-1 + 2 "), 3);
     assertEquals(calculate("(1+(4+5+2)-3)+(6+8)"), 23);