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|
require "lib/metaprogramming.nom"
require "lib/operators.nom"
require "lib/utils.nom"
# Conditionals
compile [if %condition %if_body] to code: ".."
|if \(%condition as lua) then;
|\(%if_body as lua statements)
|end;--end if
compile [unless %condition %body] to code: ".."
|if not (\(%condition as lua)) then;
|\(%body as lua statements)
|end;--end if
compile [if %condition %if_body else %else_body, unless %condition %else_body else %if_body] to code: ".."
|if \(%condition as lua) then;
|\(%if_body as lua statements)
|else;
|\(%else_body as lua statements)
|end;--end if
# Return
compile [return] to code: "do; return; end;"
compile [return %return-value] to code: "do; return \(%return-value as lua); end;"
# GOTOs
compile [-> %label] to code: ".."
|::label_\(nomsu "var_to_lua_identifier" [%label])::;
compile [go to %label] to code: ".."
|goto label_\(nomsu "var_to_lua_identifier" [%label]);
rule [tree %tree has function call %call] =:
lua code ".."
|local target = (\(%call)).value;
|for subtree,_ in coroutine.wrap(function() nomsu:walk_tree(\(%tree)); end) do;
| if type(subtree) == 'table' and subtree.type == "FunctionCall"
| and nomsu.utils.equivalent(subtree.value, target, 2) then;
| return true;
| end;
|end;
|do; return false; end;
# While loops
compile [do next repeat-loop] to code: "goto continue_repeat;"
compile [stop repeat-loop] to code: "goto stop_repeat;"
compile [repeat while %condition %body] to code:
%continue-labels = (..)
"\n::continue_repeat::;" if (tree %body has function call \(do next repeat-loop)) else ""
%code = ".."
|while \(%condition as lua) do;
|\(%body as lua statements)\(%continue-labels)
|end;--while-loop
if (tree %body has function call \(stop repeat-loop)):
return ".."
|do;--while-loop label scope
|\(%code)
|::stop_repeat::;
|end;--while-loop label scope
return %code
parse [repeat %body] as: repeat while (true) %body
parse [repeat until %condition %body] as: repeat while (not %condition) %body
# For loop control flow:
compile [stop for-loop] to code: "goto stop_for;"
compile [stop %var] to code: ".."
|goto stop_\(nomsu "var_to_lua_identifier" [%var]);
compile [do next for-loop] to code: "goto continue_for;"
compile [do next %var] to code: ".."
|goto continue_\(nomsu "var_to_lua_identifier" [%var]);
# Numeric range for loops
compile [..]
for %var from %start to %stop by %step %body
for %var from %start to %stop via %step %body
..to code:
%continue-labels = ""
if (tree %body has function call \(do next for-loop)):
%continue-labels join= "\n::continue_for::;"
if (tree %body has function call (nomsu "replaced_vars" [\(do next %), lua expr "{['']=\(%var)}"])):
%continue-labels join= "\n::continue_\(nomsu "var_to_lua_identifier" [%var])::;"
%code = ".."
|for i=\(%start as lua),\(%stop as lua),\(%step as lua) do;
# This trashes the loop variables, just like in Python.
|\(%var as lua) = i;
|\(%body as lua statements)\(%continue-labels)
|end;--numeric for-loop
%stop-labels = ""
if (tree %body has function call \(stop for-loop)):
%stop-labels join= "\n::stop_for::;"
if (tree %body has function call (nomsu "replaced_vars" [\(stop %), lua expr "{['']=\(%var)}"])):
%stop-labels join= "\n::stop_\(nomsu "var_to_lua_identifier" [%var])::;"
if (%stop-labels != ""): ".."
|do;--for-loop label scope
|\(%code)\(%stop-labels)
|end;--for-loop label scope
..else: %code
parse [for %var from %start to %stop %body] as: for %var from %start to %stop via 1 %body
parse [..]
for all %start to %stop by %step %body
for all %start to %stop via %step %body
..as: for % from %start to %stop via %step %body
parse [for all %start to %stop %body] as: for all %start to %stop via 1 %body
compile [for %var in %iterable %body] to code:
%continue-labels = ""
if (tree %body has function call \(do next for-loop)):
%continue-labels join= "\n::continue_for::;"
if (tree %body has function call (nomsu "replaced_vars" [\(do next %), lua expr "{['']=\(%var)}"])):
%continue-labels join= "\n::continue_\(nomsu "var_to_lua_identifier" [%var])::;"
%code = ".."
|for i,value in ipairs(\(%iterable as lua)) do;
# This trashes the loop variables, just like in Python.
|\(%var as lua) = value;
|\(%body as lua statements)\(%continue-labels)
|end;--foreach-loop
%stop-labels = ""
if (tree %body has function call \(stop for-loop)):
%stop-labels join= "\n::stop_for::;"
if (tree %body has function call (nomsu "replaced_vars" [\(stop %), lua expr "{['']=\(%var)}"])):
%stop-labels join= "\n::stop_\(nomsu "var_to_lua_identifier" [%var])::;"
if (%stop-labels != ""): ".."
|do;--for-loop label scope
|\(%code)\(%stop-labels)
|end;--for-loop label scope
..else: %code
parse [for all %iterable %body] as: for % in %iterable %body
# Switch statement/multi-branch if
compile [when %body] to code:
%result = ""
%fallthroughs = []
%first = (yes)
for %func-call in (%body's "value"):
assert ((%func-call's "type") == "FunctionCall") ".."
|Invalid format for 'when' statement. Only '*' blocks are allowed.
%tokens = (%func-call's "value")
%star = (%tokens -> 1)
assert (lua expr "vars.star and vars.star.type == 'Word' and vars.star.value == '*'") ".."
|Invalid format for 'when' statement. Lines must begin with '*'
%condition = (%tokens -> 2)
assert %condition ".."
|Invalid format for 'when' statement. Lines must begin with '*' and have a condition or the word "else"
%action = (%tokens -> 3)
if (%action == (nil)):
lua block "table.insert(vars.fallthroughs, vars.condition)"
do next %func-call
if (lua expr "vars.condition.type == 'Word' and vars.condition.value == 'else'"):
%result join= ".."
|
|else;
|\(%action as lua statements)
stop for-loop
..else:
%condition = (%condition as lua)
for all %fallthroughs:
%condition join= " or \(% as lua)"
%result join= ".."
|
|\("if" if %first else "elseif") \(%condition) then;
|\(%action as lua statements)
%fallthroughs = []
%first = (no)
if (%result != ""):
%result join= "\nend;"
%result
# Switch statement
compile [when %branch-value == ? %body] to code:
%result = ""
%fallthroughs = []
%first = (yes)
for %func-call in (%body's "value"):
assert ((%func-call's "type") == "FunctionCall") ".."
|Invalid format for 'when' statement. Only '*' blocks are allowed.
%tokens = (%func-call's "value")
%star = (%tokens -> 1)
assert (lua expr "vars.star and vars.star.type == 'Word' and vars.star.value == '*'") ".."
|Invalid format for 'when' statement. Lines must begin with '*'
%condition = (%tokens -> 2)
assert %condition ".."
|Invalid format for 'when' statement. Lines must begin with '*' and have a condition or the word "else"
%action = (%tokens -> 3)
if (%action == (nil)):
lua block "table.insert(vars.fallthroughs, vars.condition)"
do next %func-call
if (lua expr "vars.condition.type == 'Word' and vars.condition.value == 'else'"):
%result join= ".."
|
|else;
|\(%action as lua statements)
stop for-loop
..else:
%condition = "branch_value == (\(%condition as lua))"
for all %fallthroughs:
%condition join= " or (branch_value == \(% as lua))"
%result join= ".."
|
|\("if" if %first else "elseif") \(%condition) then;
|\(%action as lua statements)
%fallthroughs = []
%first = (no)
if (%result != ""):
%result = ".."
|do;--when == ?
|local branch_value = \(%branch-value as lua);\(%result)
|end;
|end;--when == ?
%result
# With statement
compile [with %thing = %value %action] to code: ".."
|do;
| local old_value = \(%thing as lua);
| \(%thing as lua) = \(%value as lua);
| \(%action as lua statements);
| \(%thing as lua) = old_value;
|end;
|
