Alectryon displays local definitions (with set, pose) as declarations

[Casteran]

In the following proof, alectryon AlectryonIssue.v --backend latex builds a document where the variable z is presented as a simple declaration z: nat and not z := Nat.max x y : nat, which makes the displayed sub-goals apparently unsolvable.

Require Import Arith Lia.

(* begin snippet LProof *)
 Lemma L: forall x y, exists z:nat, x <= z /\ y <= z.
 Proof.  
  intros x y; pose (z := Nat.max x y). 
  exists z. 
  split; lia.
 Qed.  
(* end snippet LProof *)

Indeed, the displayed sub-goal

x, y: nat    z:nat
---------------
x <= z /\ y <= z

is unsolvable, but if the definition z := max x y: nat were displayed, the generated doc would be OK.

I noticed this issue only in Latex output mode. My alectryon version is Alectryon v1.5.0-dev

Note: this issue occurs also in the CI of hydra-battles on the top of page 227 of the doc (file https://github.com/coq-community/hydra-battles/blob/master/theories/ordinals/MoreAck/AckNotPR.v ).

[Casteran]

Looks to be an issue specific to Latex output generation.
The html file generated by the same snippet is OK w.r.t. the display of local definitions x:= A: t, whilst they appear as x: tin the pdf document.

I didn't test the other output formats.

[Casteran]

Cc: @cpitclaudel

Here is a simpler example:

(* begin snippet LProof *)
 Lemma L: exists z: bool, negb z = true.
 Proof.  
  pose (z := false). 
  exists z. 
  (* error in latex output : *)
  reflexivity.
 Qed.  
(* end snippet LProof *)

On the html output, the goal just before reflexivity is correctly displayed.
On the latex/pdf output, this goal is printed as:

z: bool
===========
negb z = true

Which is clearly unsolvable.

[Casteran]

This issue seems to be solved if one replaces in latex.py the method gen_hyp
with

 def gen_hyp(self, hyp):
        names = self.gen_names(hyp.names)
        hbody = [self.gen_code(hyp.body)] if hyp.body else []
        with macros.hyp(args=[names], optargs=hbody, verbatim=True):
           self.gen_code(hyp.type)
           if hyp.body != None:
               self.gen_txt(r":= ")
               self.gen_code(hyp.body)
           self.gen_txt(r" ")
           self.gen_mrefs(hyp)

This change has been tested successfully on the hydra-battles book.
Could someone have a look and improve the python code ?
Being a Python beginner, I didn't dare to open a PR with poor style.

Nevertheless, it would be fine to fix this issue before the next release.