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It sure makes me wonder if Ethereum would do better with a less forgiving programming language. The fact that the syntax resembles Javascript is not reassuring,

• Zyst 9y ago
  >In general, the easier the code is to read, and the harder it is to write Do you have any actual basis to back this up? My counterpoint would be Golang, which is designed exactly to be simple, and is usually really easy to read. As in, I haven't found another language where jumping into a library and reading the internals is easier than in Golang. EDIT: A counterpoint is JavaScript, a language which I use in my day to day, and similarly has quite simple syntax. But I can have trouble understanding what is going on depending on the tools used in the local environment.
  • saghm 9y ago
    I think you might be misinterpreting what GP is saying by trimming the end of the quote; they're not saying that making something easier to read makes it harder to write, they're saying that making something easy to read but hard to write is a worthy goal.
    • serhei 9y ago
      Thanks, I edited my comment to be more readable.
    • xg15 9y ago
      Also, I think "hard to write" is meant as "require that critical or dangerous details are written explicitly; if a feature adds convenience for writing at the expense of reading, it should be avoided". (Type inference, overloads and reflection come to mind) I think (hope) that no one is advocating making a language verbose or complex for it's own sake.
      • kronos29296 9y ago
        Like Rust? Rust does most of those things wrt explicit dangerous behaviour.
        • xg15 9y ago
          Exactly.
  • jchw 9y ago
    Golang is actually a good example of harder to write imo. It has good tooling that makes life easier, but unused variables, unused imports, and a lot of other things are errors. And if you do somewhat standard linting on top, it gets even more tedious. Frankly if it weren't for the tooling I'd not be very sold on Go. The tooling totally sells it for me.
• serhei 9y ago
  Heck, the basic methods of writing provably correct programs have been explained in plain English since at least the 70s: https://www.amazon.com/Discipline-Programming-Edsger-W-Dijkstra/dp/013215871X https://www.amazon.com/Discipline-Programming-Edsger-W-Dijks... https://www.amazon.com/Science-Programming-Monographs-Computer/dp/0387964800 https://www.amazon.com/Science-Programming-Monographs-Comput... This is not some rocket science type verification with a dependently typed theorem prover language, it's fairly simple paper and pencil logic. It should not be hard to adapt it to Solidity specific concepts like running out of gas. The reason these techniques are mostly ignored is that the techniques don't scale at all to large programs calling APIs with imprecise semantics (e.g. filesystem, network), and most people would rather publish imperfect software and iterate rather than spec everything up front. Well, unlike most software, contracts are not large, their semantics are meant to be 100% precise, and most people would rather take the time to make sure a contract does what it claims to do rather than discover a bug afterwards. I would hope.
  • skybrian 9y ago
    Calling it "imprecise semantics" is quite the understatement. The environment software runs in is often scarcely understood at all. Operating systems and web browsers change without notice due to auto-upgrades. Libraries are often used without understanding their implementations, and they're also constantly being upgraded. Users can install plugins that introduce bugs that can't be reproduced in the test environment. You can't build an accurate mathematical model of an environment you haven't observed. Integration tests (run against many platforms) and production logging help, but there are still plenty of unknowns.
    • simplify 9y ago
      How do you normally handle those unknowns?
      • serhei 9y ago
        Imitating other code that is known to work [1]. Lots of testing. Fixing the bug when someone runs into it and complains (a viable last-resort for almost anything besides a Solidity contract). [1]: For example, when working with filesystems, people write code that they saw other people using. The code may or may not work as designed depending on the specific filesystem. see e.g. https://danluu.com/file-consistency/ https://danluu.com/file-consistency/
• spopejoy 9y ago
  > It sure makes me wonder if Ethereum would do better with a less forgiving programming language. This will be hard. While Solidity certainly has problems unto itself, some of its insecurity comes from the EVM's design, which is almost laughably low level and thus very hard to reason about. It certainly doesn't seem to be informed by modern VMs like LLVM, JVM or BEAM, which know a great deal more about the semantics of the program they're running and have things like dispatching features. My guess is the approach was "Bitcoin with a few more opcodes" and therefore more like a 80s-era CPU than a "VM". As a result, the compiler is tasked with running the whole show. Add to this the coupling of RPC to Solidity's mangle-check-and-jump dispatch approach, and you start to see why there's been so little innovation in this area: Solidity has a tight grip on the Ethereum ecosystem. Also, writing a compiler to this substrate is not easy, and you're penalized for code size (there's a limit on how big a contract can be). I'm opinionated, as an author of a competing smart contract language (http://kadena.io/pact http://kadena.io/pact) that runs in an interpreter, is Turing-incomplete, has single-assignment variables etc etc which we think makes a lot more sense for the kind of stylized computing you're doing on a blockchain. We even have the ability to compile our code to SMT-LIB2 for use with the Z3 theorem prover and will be talking more soon about our DSL for writing proofs. Interestingly though, we find that choosing the right domain for your language goes a long way towards safety AND expressiveness, so that you're not constantly cursing your compiler/interpreter while also worrying less about $50M exploits :)
  • ghthor 9y ago
    What would be the complications in providing a transpiler for pact into Solidity?
    • spopejoy 9y ago
      It's possible, but impractical: - Pact executes in a runtime environment that at a minimum ensures any ED25519 signatures on the transaction are valid, such that code can then test the validated public keys to enforce authorization rules. So this would need to happen before each transaction, which would assuredly be super-expensive gas-wise. - Pact modules (i.e., contracts in the Solidity sense) export functions on-chain that can then be imported/invoked by other modules by name, thus allowing safe inter-contract communication, on-chain services, and other nice things. This model is very foreign to Solidity where inter-contract communication is poorly supported; best practices there dictate copy-pasting approved code (c.f. ERC 20 tokens) and hosting all functionality in-contract. - Pact being interpreted is hugely valuable on-chain, as you can directly inspect human-readable code, as opposed to EVM assembly/opcodes. This is more of a philosophical point though. - Other things, like supporting direct storage of JSON objects in the database, exporting Pact types as JSON (which you get for free in the Pact runtime), key/value db functionality, transaction history at the db level, support for governance in upgrades -- all of these would need to be coded in as Solidity code, with great computational expense. The biggest issue facing Solidity developers today is the sheer cost of best practices: ensuring you handle overflows right (ie don't use math primitives but call an approved function), planning for upgrades/data export, you name it: you have to use that code and pay that gas. The environment really needs to provide a lot more "free" functionality than it does today to change this reality.
• SolarNet 9y ago
  Exactly, this is a language that they want to run a new economy, not just payment processing, but banking, title transfer, legal resolutions, and the metric it was judged on was "looks like javascript" and not say: * Compiler time safety (type safety, capabilities, rust and/or haskell style features). * Built in formal verification features to ensure a function does what the developer (and reader!) thinks and no cases are missed. * Explicit language design (so that the compiler isn't even required to do strong safety: every action must be spelled out, even if a compiler could deduce it). * Paying attention to the fucking history of the field (and not doing things like: insane name mangling, case sensitive semantics (not even just names by convention fucking semantics are case sensitive), hard to reason about VMs). Like come on people, at least learn from 20+ year old mistakes.
  • peoplewindow 9y ago
    Solidity has far worse problems than not being an advanced research language. Just being a sanely designed normal language would be a big step up. Solidity is so riddled with bizarre design errors it makes PHP 4 look like a work of genius. A small sampling of the issues: Everything is 256 bits wide, including the "byte" type. This means that whilst byte[] is valid syntax, it will take up 32x more space than you expect. Storage space is extremely limited in Solidity programs. You should use "bytes" instead which is an actual byte array. The native 256-bit wide primitive type is called "bytes32" but the actual 8-bit wide byte type is called "int8". Strings. What can we say about this. There is a string type. It is useless. There is no support for string manipulation at all. String concatenation must be done by hand after casting to a byte array. Basics like indexOf() must also be written by hand or implementations copied into your program. To even learn the length of a string you must cast it to a byte array, but see above. In some versions of the Solidity compiler passing an empty string to a function would cause all arguments after that string to be silently corrupted. There is no garbage collector. Dead allocations are never reclaimed, despite the scarcity of available memory space. There is also no manual memory management. Solidity looks superficially like an object oriented language. There is a "this" keyword. However there are actually security-critical differences between "this.setX()" and "setX()" that can cause wrong results: https://github.com/ethereum/solidity/issues/583 https://github.com/ethereum/solidity/issues/583 Numbers. Despite being intended for financial applications like insurance, floating point is not supported. Integer operations can overflow, despite the underlying operation being interpreted and not implemented in hardware. There is no way to do overflow-checked operations: you need constructs like "require((balanceOf[_to] + _value) >= balanceOf[_to]);" You can return statically sized arrays from functions, but not variably sized arrays. For loops are completely broken. Solidity is meant to look like JavaScript but the literal 0 type-infers to byte, not int. Therefore "for (var i = 0; i < a.length; i ++) { a[i] = i; }" will enter an infinite loop if a[] is longer than 255 elements, because it will wrap around back to zero. This is despite the underlying VM using 256 bits to store this byte. You are just supposed to know this and write "uint" instead of "var". Arrays. Array access syntax looks like C or Java, but array declaration syntax is written backwards: int8[][5] creates 5 dynamic arrays of bytes. Dynamically sized arrays work, in theory, but you cannot create multi-dimensional dynamic arrays. Because "string" is a byte array, that means "string[]" does not work. The compiler is riddled with mis-compilation bugs, many of them security critical. The documentation helpfully includes a list of these bugs .... in JSON. The actual contents of the JSON is of course just strings meant to be read by humans. Here are some summaries of miscompile bugs: In some situations, the optimizer replaces certain numbers in the code with routines that compute different numbers Types shorter than 32 bytes are packed together into the same 32 byte storage slot, but storage writes always write 32 bytes. For some types, the higher order bytes were not cleaned properly, which made it sometimes possible to overwrite a variable in storage when writing to another one. Dynamic allocation of an empty memory array caused an infinite loop and thus an exception Access to array elements for arrays of types with less than 32 bytes did not correctly clean the higher order bits, causing corruption in other array elements. As you can see the decision to build a virtual machine with that is natively 256-bit wide led to a huge number of bugs whereby reads or writes randomly corrupt memory. Solidity/EVM is by far the worst programming environment I have ever encountered. It would be impossible to write even toy programs correctly in this language, yet it is literally called "Solidity" and used to program a financial system that manages hundreds of millions of dollars.
• biafra 9y ago
  Nobody prevents you to write contracts in a more restrictive language. For example: https://github.com/ethereum/viper https://github.com/ethereum/viper Or create your own. I am sure the creators of Solidity are aware of its limitations and quirks. But as far as I can tell they felt they had to ome up with something fast. And it grew from there. But as I said: Feel free to create your own language for the EVM if Solidity does not fit your needs or requirements. With a system allowing Turing completenes it should be possible to create a language that removes Turing completeness (for more security). It would be impossible the other way round.