Proper placement of "e.g." [duplicate]

Question

I am a little bit confused after I found out that "e.g." is followed by a comma in American English. My confusion stems from the correct placement of this abbreviation. Consider the following sentence:

Usually, these entities are both represented in the source language, e.g., as modules or top-level declarations, and easy to distinguish from each other by the user and the compiler, e.g., as separate files or directories.

When reading this sentence, I stumble upon the commas after the "e.g."s. I could understand it if the sentence was:

Usually, these entities are both represented in the source language, as, e.g., modules or top-level declarations, and easy to distinguish from each other by the user and the compiler, as, e.g., separate files or directories.

The second version reads somewhat slower, there is more emphasis on the ".e.g." as I would like and the meaning of the second "as" might be confused to relate to the "compiler".

Is the first form correct? If so, I wonder what purpose the commas serve? Is the second version different in meaning from the first, or am I reading it wrong?

Answer 1

The first form is correct (but read on). As you probably know, "e.g." is an abbreviation of the Latin exempli gratia, which means “for the sake of example” or more simply, "for example." By convention, there is no space between "e." and "g.," and "e.g." is followed by a comma in American English.

This article notes,

The Chicago Manual of Style states that i.e. and e.g. should be “confined to parentheses and notes and followed by a comma.”

The AP [Associated Press] Stylebook, whose “punctuation-pitch” leans generally to the side of “the fewer commas the better,” is pro-comma when it comes to i.e. and e.g. According to AP, both abbreviations are “always followed by a comma.”

The same article points out,

The Penguin Writer’s Manual (British) shows both i.e. and e.g. without a following comma.

and offers the following advice:

As with so many matters of punctuation, the writer’s best practice is to choose a style reference and follow its recommendations.

Many writers choose to avoid its use and instead write plainly, "for example."

You may also find the answers to this EL&U post useful.