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Better representation for Go's defer #87
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My first idea was to add deferred nodes when they need to be, and have a dotted or dashed arrow leading to them from the original
deferline.
Sadly, this becomes an unreadable mess.digraph "" { node [shape=box, color="#000000" label=""]; edge [headport=n tailport=s] bgcolor="#ffffff" node0 [style="filled"; label=""; id="node0"; shape="invhouse"; class="entry"; fillcolor="#48AB30"; height=0.5]; node1 [style="filled"; label=""; id="node1"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node2 [style="filled"; label=""; id="node2"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node4 [style="filled"; label=""; id="node4"; shape="house"; class="exit"; fillcolor="#AB3030"; height=0.5]; node3 [style="filled"; label=""; id="node3"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node5 [style="filled"; label=""; id="node5"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node6 [style="filled"; label=""; id="node6"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node7 [style="filled"; label=""; id="node7"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node9 [style="filled"; label=""; id="node9"; shape="house"; class="exit"; fillcolor="#AB3030"; height=0.5]; node8 [style="filled"; label=""; id="node8"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node10 [style="filled"; label=""; id="node10"; shape="box"; class="default"; fillcolor="#d3d3d3"; height=0.3]; node11 [style="filled"; label=""; id="node11"; shape="house"; class="exit"; fillcolor="#AB3030"; height=0.5]; node2 -> node4 [penwidth=1; color="#008000"; class="consequence"]; node2 -> node3 [penwidth=1; color="#ff0000"; class="alternative"]; node7 -> defer5_a [penwidth=1; color="#008000"; class="consequence"]; node5 -> defer5_a [tailport=w headport=w style="dashed"] defer5_a -> node9 [penwidth=1; color="#0000ff"; class="regular"]; node7 -> node8 [penwidth=1; color="#ff0000"; class="alternative"]; node1 -> node2 [penwidth=1; color="#0000ff"; class="regular"]; node3 -> node5 [penwidth=1; color="#0000ff"; class="regular"]; node5 -> node6 [penwidth=1; color="#0000ff"; class="regular"]; node6 -> node7 [penwidth=1; color="#0000ff"; class="regular"]; node8 -> node10 [penwidth=1; color="#0000ff"; class="regular"]; node10 -> defer10 [penwidth=1; color="#0000ff"; class="regular"]; node0 -> node1 [penwidth=1; color="#0000ff"; class="regular"]; node5 -> defer5 [tailport=w headport=w style="dashed"] node10 -> defer10 [tailport=w headport=w style="dashed"] defer5 -> node11 [penwidth=1; color="#0000ff"; class="regular"]; defer10 -> defer5 [penwidth=1; color="#0000ff"; class="regular"]; }
Next option is to use something similar to Python's context manager:
But I don't know if Go devs think of
deferthat way, so it feels weird.Additionally, it's not always a truthful representation.
A conditionaldefer(inside anif) would not lead to a context-like behavior.Unlike context-managers and exceptions,
defer's scope doesn't match the lexical scope in which it is used.I also thought of doing a node to the side of the "defer" line, but that is, again, messy.
We could also make it similar to
yield, with it's own node shape.
But I feel it is still different, asyieldaffects the local control flow where defer does not.Maybe an icon? Or a texture?
I really don't know what to go for here.Another issue with
deferis that we don't know the order in which defers will happen.Consider the following:
package main import ( "fmt" ) func withDefer(flags ...bool) { for _, flag := range flags { if flag { defer fmt.Println("True") } else { defer fmt.Println("False") } } } func main() { withDefer(true, false) withDefer(false, true) }
What would be a good representation here?
I am starting to think that the best approach would be to add a new block type for it (like
yield).
Currently there is no special treatment for
defer.This needs to be improved, as
deferis a control-flow structure, and a rather complex one at that.