Ethereum Smart Contract Development

Pragma, import, and comments

A pragma directive of solidity always has versions in the form 0.x.0 or x .0.0, as shown in Figure 6.1. This ensures that any future version of the solidity compiler is ignored that might introduce incompatibility:

Figure 6.1: Pragma directives

Although solidity does not have the ability to export or spool-out results yet, it supports import statements, which are very similar to JavaScript. This keyword is used at contract compile time in our local build environment. Once a contract gets deployed on a blockchain using EVM, it can neither read nor write files. Figure 6.2, lists down a few uses of the import statement ...