feat(cli): constant expression evaluation

.github/workflows/tact.yml

@@ -113,6 +113,10 @@ jobs:
         run: |
           ! tact --config bin/test/fail.config.json
 
+      - name: CLI Test | Evaluate expression
+        run: |
+          tact -e '(1 + 2 * (pow(3,4) - 2) << 1 & 0x54 | 33 >> 1) * 2 + 2'
+
       - name: Link Tact compiler
         run: |
           yarn link

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- `-e` / `--eval` CLI flags to evaluate constant Tact expressions: PR [#462](https://github.com/tact-lang/tact/pull/462)
+
 ### Changed
 
 ### Fixed

bin/tact

@@ -19,6 +19,7 @@ meowModule.then(
       --with-decompilation        Full compilation followed by decompilation of produced binary code
       --func                      Output intermediate FunC code and exit
       --check                     Perform syntax and type checking, then exit
+      -e, --eval EXPRESSION       Evaluate a Tact expression and exit
       -v, --version               Print Tact compiler version and exit
       -h, --help                  Display this text and exit
 
@@ -39,18 +40,21 @@ meowModule.then(
             shortFlag: "c",
             type: "string",
             isRequired: (flags, _) => {
-              // Require a config when the projects are specified AND version/help are not specified
-              if (
+              // Require a config when the projects are specified
+              // AND version/help are not specified
+              // AND eval is not specified
+              return (
                 flags.projects.length !== 0 &&
                 !flags.version &&
-                !flags.help
-              ) {
-                return true;
-              }
-              // Don't require it otherwise
-              return false;
+                !flags.help &&
+                !flags.eval
+              );
             },
           },
+          eval: {
+            shortFlag: "e",
+            type: "string",
+          },
           projects: { shortFlag: "p", type: "string", isMultiple: true },
           withDecompilation: { type: "boolean", default: false },
           func: { type: "boolean", default: false },
@@ -64,10 +68,7 @@ meowModule.then(
 
     // Helper function to write less in following checks
     const isEmptyConfigAndInput = () => {
-      if (cli.flags.config === undefined && cli.input.length === 0) {
-        return true;
-      }
-      return false;
+      return cli.flags.config === undefined && cli.input.length === 0;
     };
 
     // Show help regardless of other flags
@@ -80,6 +81,21 @@ meowModule.then(
       cli.showVersion();
     }
 
+    // Evaluate expression regardless of other flags
+    if (cli.flags.eval) {
+      const result = main.parseAndEvalExpression(cli.flags.eval);
+      switch (result.kind) {
+        case "ok": {
+          console.log(result.value);
+          process.exit(0);
+        }
+        case "error": {
+          console.log(result.message);
+          process.exit(30);
+        }
+      }
+    }
+
     // Disallow specifying both config or Tact source file at the same time
     if (cli.flags.config !== undefined && cli.input.length > 0) {
       console.log(

src/grammar/grammar.ts

@@ -3,6 +3,7 @@ import {
     ASTAugmentedAssignOperation,
     ASTConstantAttribute,
     ASTContractAttribute,
+    ASTExpression,
     ASTFunctionAttribute,
     ASTNode,
     ASTProgram,
@@ -1189,6 +1190,14 @@ export function parse(
     });
 }
 
+export function parseExpression(sourceCode: string): ASTExpression {
+    const matchResult = rawGrammar.match(sourceCode, "Expression");
+    if (matchResult.failed()) {
+        throwParseError(matchResult, "");
+    }
+    return semantics(matchResult).astOfExpression();
+}
+
 export function parseImports(
     src: string,
     path: string,

src/interpreter.ts

@@ -0,0 +1,27 @@
+import { evalConstantExpression } from "./constEval";
+import { CompilerContext } from "./context";
+import { TactConstEvalError, TactParseError } from "./errors";
+import { parseExpression } from "./grammar/grammar";
+import { Value } from "./types/types";
+
+export type EvalResult =
+    | { kind: "ok"; value: Value }
+    | { kind: "error"; message: string };
+
+export function parseAndEvalExpression(sourceCode: string): EvalResult {
+    try {
+        const ast = parseExpression(sourceCode);
+        const constEvalResult = evalConstantExpression(
+            ast,
+            new CompilerContext(),
+        );
+        return { kind: "ok", value: constEvalResult };
+    } catch (error) {
+        if (
+            error instanceof TactParseError ||
+            error instanceof TactConstEvalError
+        )
+            return { kind: "error", message: error.message };
+        throw error;
+    }
+}

src/node.ts

@@ -122,3 +122,5 @@ export async function run(args: {
 }
 
 export { createNodeFileSystem } from "./vfs/createNodeFileSystem";
+
+export { parseAndEvalExpression } from "./interpreter";