rules | 易学教程

How to write files to current directory instead of bazel-out

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I have the following directory structure: my_dir | --> src | | | --> foo.cc | --> BUILD | --> WORKSPACE | --> bazel-out/ (symlink) | | ... src/BUILD contains the following code: cc_binary( name = "foo", srcs = ["foo.cc"] ) The file foo.cc creates a file named bar.txt using the regular way with <fstream> utilities. However, when I invoke Bazel with bazel run //src:foo the file bar.txt is created and placed in bazel-out/darwin-fastbuild/bin/src/foo.runfiles/foo/bar.txt instead of my_dir/src/bar.txt , where the original source is. I tried adding an outs field to the foo rule, but Bazel complained

What are the rules for function pointers and member function pointers to Standard functions?

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What are the existing rules for taking function pointers or member function pointers to Standard functions? For example, something like auto p = &std::string::size; Is this legal? Would it be more or less legal if I explicitly requested the correct type, so it would function even if there was an additional implementation-added overload of std::string::size ? Using the "correct" type doesn't make things better: Except for the virtual functions all functions in the standard C++ library can have additional arguments as long as these are defaulted. Since the functions can also be declared with

Rules engine for .NET

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问题 We have a business requirement to let power users edit rules for insurance rates and enrollments. We need a web ui that lets them say "this product is only for people <55 unless they are from Texas and own a poodle" or whatever. Edit for clarification: Insurance is insane. The rules differ from product to product, state to state and change constantly. We looked at a couple of rules engines but the commercial ones are 100K+ and the open source ones don't seem um, finished. Windows Workflow

elementui的表格嵌套表单及校验demo

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你在使用vue+elementUI技术栈的时候，有没有碰到表格嵌套表单需求以及需要前台的一个校验？这里为大家写了一个demo: 1 <template> 2 <div> 3 <el-form :model="forms" ref="forms" :rules="rules"> 4 <el-table :data="forms.voList"> 5 <el-table-column 6 label="商品名称"> 7 <template slot-scope="scope"> 8 <el-form-item :prop="'voList.'+scope.$index+'.goodsName'"> 9 <el-input v-model="scope.row.goodsName"></el-input> 10 </el-form-item> 11 </template> 12 </el-table-column> 13 <el-table-column 14 label="商品编码"> 15 <template slot-scope="scope"> 16 <el-form-item :prop="'voList.'+scope.$index+'.goodsCode'"> 17 <el-input v-model="scope.row.goodsCode"></el-input>

Implementing a “rules engine” in Python

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I'm writing a log collection / analysis application in Python and I need to write a "rules engine" to match and act on log messages. It needs to feature: Regular expression matching for the message itself Arithmetic comparisons for message severity/priority Boolean operators I envision An example rule would probably be something like: (message ~ "program\\[\d+\\]: message" and severity >= high) or (severity >= critical) I'm thinking about using PyParsing or similar to actually parse the rules and construct the parse tree. The current (not yet implemented) design I have in mind is to have

Is this rule about volatile usage strict?

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I've seen this sentence: the general rule is, if you have variables of primitive type that must be shared among multiple threads, declare those variables volatile from this article , and this sentence: In general, any data that may be undated asynchronously should be declared to be volatile. from this page , now considering this introduced rule I'd like to know could you bring an example of a case where despite existence of asynchronous access to a data declaring that data volatile has no use in practice or there's no such exceptional case and the rule is strict. sbi I remember when that

makefile pattern rules without recipes

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I'm observing an interesting behavior of make and I wonder if there is a reasonable explanation to it besides a bug in gmake. Let's say we have the following in makefile: %-animal: echo "$* is an animal" %-fox: %-fox-animal %-wolf: %-wolf-animal The difference between the last two targets is that "%-wolf" does not have any recipe, and "%-fox" has an empty recipe (i.e. just a line with a tab at the beginning). When we try to execute the rules, here's what happens: [root@cv19 tmp]# make freddy-animal echo "freddy is an animal" freddy is an animal [root@cv19 tmp]# make freddy-wolf make: *** No

prevent “delete and update” a child in firebase

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问题 I see that there is no way to set security rules as preventing "delete and update" for a child. ".write": "!data.exists() && newData.exists() && !newData.exists()" thats not make sense. 回答1: For future reference, the Firebase console lets you test database security rules, so you can find out what works right there before you publish those rules. That being said, if I'm understanding your question correctly, you want to allow users to add to the node, but not delete or update. You'd be looking

How to prevent deletion of the first row in table (PostgreSQL)?

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问题 Is it possible to prevent deletion of the first row in table on PostgreSQL side? I have a category table and I want to prevent deletion of default category as it could break the application. Of course I could easily do it in application code, but it would be a lot better to do it in database. I think it has something to do with rules on delete statement, but I couldn't find anything remotely close to my problem in documentation. 回答1: The best way I see to accomplish this is by creating a

What are PostgreSQL RULEs good for?

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Question I often see it stated that rules should be avoided and triggers used instead . I can see the danger in the rule system, but certainly there are valid uses for rules, right? What are they? I'm asking this out of general interest; I'm not very seasoned with databases. Example of what might be a valid use For instance, in the past I've needed to lock down certain data, so I've done something like this: CREATE OR REPLACE RULE protect_data AS ON UPDATE TO exampletable -- another similar rule for DELETE WHERE OLD.type = 'protected' DO INSTEAD NOTHING; Then if I want to edit the protected