adding regular expression contracts

Author: disnet

doc/main/contracts.md

@@ -100,6 +100,22 @@ first-order properties (things like `typeof` checks).
 | `Void`      | Either `null` or `undefined`           |
 
 
+### Regular Expressions
+
+You can test that a value matches a regular expression by using a
+regular expression literal:
+
+```js
+@ (/username:\s*[a-zA-Z]*$/) -> Bool
+function checkUsername(str) {
+    // ...
+    return true;
+}
+
+checkUsername("username: bob");  // passes
+checkUsername("user: bob");      // fails
+```
+
 ### Custom Predicate Contracts
 
 All of the basic contracts are built with predicates (functions that

macros/disabled.js

@@ -465,8 +465,11 @@ let import = macro {
             });
         return c;
     }
-    function self() {
-        var name = 'self';
+    function reMatch(re) {
+        var contractName = re.toString();
+        return check(function (val) {
+            return re.test(val);
+        }, contractName);
     }
     function and(left, right) {
         if (!(left instanceof Contract)) {
@@ -571,13 +574,10 @@ let import = macro {
             return null == val;
         }, 'Null'),
         check: check,
+        reMatch: reMatch,
         fun: fun,
         or: or,
         and: and,
-        self: new Contract('self', 'self', function (b) {
-            return function () {
-            };
-        }),
         repeat: repeat,
         optional: optional,
         object: object,
@@ -731,8 +731,25 @@ macro predicate_contract {
     }
 }
 
+macro regex {
+    case {_ $tok } => {
+        var tok = #{$tok};
+        if (tok[0].token.type === parser.Token.RegularExpression) {
+            return tok;
+        }
+        throwSyntaxCaseError("Not a regular expression");
+    }
+}
+
+macro regex_contract {
+    rule { $re:regex } => {
+        _c.reMatch($re)
+    }
+}
+
 
 macro non_bin_contract {
+    rule { $contract:regex_contract }     => { $contract }
     rule { $contract:predicate_contract } => { $contract }
     rule { $contract:function_contract }  => { $contract }
     rule { $contract:object_contract }    => { $contract }

macros/index.js

@@ -465,8 +465,11 @@ let import = macro {
             });
         return c;
     }
-    function self() {
-        var name = 'self';
+    function reMatch(re) {
+        var contractName = re.toString();
+        return check(function (val) {
+            return re.test(val);
+        }, contractName);
     }
     function and(left, right) {
         if (!(left instanceof Contract)) {
@@ -571,13 +574,10 @@ let import = macro {
             return null == val;
         }, 'Null'),
         check: check,
+        reMatch: reMatch,
         fun: fun,
         or: or,
         and: and,
-        self: new Contract('self', 'self', function (b) {
-            return function () {
-            };
-        }),
         repeat: repeat,
         optional: optional,
         object: object,
@@ -731,8 +731,25 @@ macro predicate_contract {
     }
 }
 
+macro regex {
+    case {_ $tok } => {
+        var tok = #{$tok};
+        if (tok[0].token.type === parser.Token.RegularExpression) {
+            return tok;
+        }
+        throwSyntaxCaseError("Not a regular expression");
+    }
+}
+
+macro regex_contract {
+    rule { $re:regex } => {
+        _c.reMatch($re)
+    }
+}
+
 
 macro non_bin_contract {
+    rule { $contract:regex_contract }     => { $contract }
     rule { $contract:predicate_contract } => { $contract }
     rule { $contract:function_contract }  => { $contract }
     rule { $contract:object_contract }    => { $contract }

src/contracts.js

@@ -583,8 +583,11 @@
         return c;
     }
 
-    function self() {
-        var name = "self";
+    function reMatch(re) {
+        var contractName = re.toString();
+        return check(function(val) {
+            return re.test(val);
+        }, contractName);
     }
 
     function and(left, right) {
@@ -614,6 +617,7 @@
         })
     }
 
+
     function or(left, right) {
         if (!(left instanceof Contract)) {
             if (typeof left === "function") {
@@ -674,10 +678,10 @@
         Void: check(function(val)      { return null == val; }, "Null"),
 
         check: check,
+        reMatch: reMatch,
         fun: fun,
         or: or,
         and: and,
-        self: new Contract("self", "self", function(b) { return function() {}; }),
         repeat: repeat,
         optional: optional,
         object: object,

src/macros-disabled.js

@@ -145,8 +145,25 @@ macro predicate_contract {
     }
 }
 
+macro regex {
+    case {_ $tok } => {
+        var tok = #{$tok};
+        if (tok[0].token.type === parser.Token.RegularExpression) {
+            return tok;
+        }
+        throwSyntaxCaseError("Not a regular expression");
+    }
+}
+
+macro regex_contract {
+    rule { $re:regex } => {
+        _c.reMatch($re)
+    }
+}
+
 
 macro non_bin_contract {
+    rule { $contract:regex_contract }     => { $contract }
     rule { $contract:predicate_contract } => { $contract }
     rule { $contract:function_contract }  => { $contract }
     rule { $contract:object_contract }    => { $contract }

src/macros.js

@@ -145,8 +145,25 @@ macro predicate_contract {
     }
 }
 
+macro regex {
+    case {_ $tok } => {
+        var tok = #{$tok};
+        if (tok[0].token.type === parser.Token.RegularExpression) {
+            return tok;
+        }
+        throwSyntaxCaseError("Not a regular expression");
+    }
+}
+
+macro regex_contract {
+    rule { $re:regex } => {
+        _c.reMatch($re)
+    }
+}
+
 
 macro non_bin_contract {
+    rule { $contract:regex_contract }     => { $contract }
     rule { $contract:predicate_contract } => { $contract }
     rule { $contract:function_contract }  => { $contract }
     rule { $contract:object_contract }    => { $contract }

test/test_contracts.js

@@ -904,4 +904,24 @@ function foo guarded at line: 881
 blaming: (calling context for foo)
 `
     })
+
+    it("should work for the regex contract", function() {
+        @ (/username:\s*[a-zA-Z]*$/) -> Bool
+        function checkUsername(str) {
+            return true;
+        }
+
+        checkUsername("username: bob");
+        blame of {
+            checkUsername("bad");
+        } should be `checkUsername: contract violation
+expected: /username:\s*[a-zA-Z]*$/
+given: 'bad'
+in: the 1st argument of
+    (/username:\s*[a-zA-Z]*$/) -> Bool
+function checkUsername guarded at line: 910
+blaming: (calling context for checkUsername)
+`
+
+    })
 });