When might you use the do / end syntax versus using the curly bracket syntax for a block?

In Ruby, the choice between using do...end and curly braces {...} for block syntax often depends on the context and purpose of the block, as well as stylistic preferences and conventions.

Semantic and Stylistic Considerations

1. Multi-line vs. Single-line Blocks:

   • do...end: This syntax is typically used for multi-line blocks. It is more visually distinct when spanning multiple lines, making the code easier to read and understand. This is especially useful in more complex blocks where readability is crucial[1][2][5].
   • Curly Braces {...}: These are generally preferred for single-line blocks. The compact nature of curly braces suits short, concise blocks of code that are simple enough to be written in a single line[1][5].

2. Functional vs. Procedural Context:

   • Functional Context: Curly braces are often used in functional programming contexts within Ruby, such as when chaining methods together. This usage aligns with the convention in many other programming languages and helps to maintain clarity and consistency when reading through method chains[5].
   • Procedural Context: The do...end syntax is more common in procedural contexts, where the block is intended to perform a series of operations rather than returning a value. This is often seen in scripts and more extensive code blocks within application logic[1][5].

Precedence Rules

Another technical aspect to consider is the precedence of the block delimiters. Curly braces have a higher precedence than do...end. This difference can affect how the block binds to the surrounding code, particularly in method calls with parameters.

• Higher Precedence ({...}): When using curly braces, the block will bind more tightly to the preceding expression. This is particularly relevant in nested method calls ...