metaphors - Omission of 'like' in a comparison

I started reading the Neuromancer and I'm facing a difficulty, especially in the following excerpt:

Ratz was tending bar, his prosthetic arm jerking monotonously as he filled a tray of glasses with draft Kirin. He saw Case and smiled, his teeth a webwork of East European steel and brown decay.

I assume the second sentence compares his teeth to a webwork [...], however I don't understand why the 'like' keyword is omitted in this construction.
I'd have expected something like "his teeth were like a webwork [...]".

I haven't found anything about that on Google, any idea?

Thanks,

Answer

There are two issues here: grammatical and rhetorical/literary.

Grammatically, in

[1] He saw Case and smiled, h͟i͟s͟ ͟t͟e͟e͟t͟h͟ ͟a͟ ͟w͟e͟b͟w͟o͟r͟k͟ ͟o͟f͟ ͟E͟a͟s͟t͟ ͟E͟u͟r͟o͟p͟e͟a͟n͟ ͟s͟t͟e͟e͟l͟ ͟a͟n͟d͟ ͟b͟r͟o͟w͟n͟ ͟d͟e͟c͟a͟y͟.

the underlined part is a supplement in the form of a verbless clause (CGEL, pp 1359-1360).

As was pointed out in the comments, the meaning is the same as if we had

[2] He saw Case and smiled. His teeth w͟e͟r͟e͟ a webwork of East European steel and brown decay.

More on the vebless clauses below.

Rhetorically, the difference between [1] and [2] on the one hand, and

[3] He saw Case and smiled, his teeth l͟i͟k͟e͟ a webwork of East European steel and brown decay.

on the other, is that [3] uses a simile, whereas [1] and [2] use a metaphor.

More on verbless clauses as supplements, from CGEL, pp 1359-1360. Note that supplements are 'elements which occupy a position in linear
sequence without being integrated into the syntactic structure of the sentence' (p. 1350).

(f) Verbless clause

[28] i The tourists, m͟o͟s͟t͟ ͟o͟f͟ ͟t͟h͟e͟m͟ ͟f͟o͟r͟e͟i͟g͟n͟e͟r͟s͟, had been hoarded onto a cattle truck.
        ii The defendants sat in the dock, t͟h͟e͟i͟r͟ ͟h͟e͟a͟d͟s͟ ͟i͟n͟ ͟t͟h͟e͟i͟r͟ ͟h͟a͟n͟d͟s͟.
       iii The only household chore men excelled at was - d͟r͟u͟m͟r͟o͟l͟l͟ ͟p͟l͟e͟a͟s͟e͟ - taking out the
            rubbish.

In [i] the supplement is comparable in function to a relative clause: compare who were most of them foreigners (or most of whom were foreigners). If the supplement consisted of foreigners on its own, it would be an ascriptive NP (noun phrase), like those in [22] (e.g. Her father, a͟ ͟d͟i͟e͟-͟h͟a͟r͟d͟ ͟c͟o͟n͟s͟e͟r͟v͟a͟t͟i͟v͟e͟, refused to even consider the proposal.); most of them, however, does not function as a modifier in NP structure, so most of them foreigners must be analysed as a reduced clause - one which could not stand alone as a sentence. The supplement in [28ii] could likewise not stand alone, but differs in its internal structure in that their heads is subject. An equivalent integrated construction would have a modifierwith the form of with + verbless clause: with their heads in their hands. The supplement in [28iii], by contrast, could stand alone as a sentence. It is simply a fragmentary main clause (with the illocutionary force of a directive) used as an interpolation.