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-rw-r--r--core/control_flow.nom164
1 files changed, 75 insertions, 89 deletions
diff --git a/core/control_flow.nom b/core/control_flow.nom
index b3f0978..5719d72 100644
--- a/core/control_flow.nom
+++ b/core/control_flow.nom
@@ -154,7 +154,7 @@ compile [..]
..to:
# This uses Lua's approach of only allowing loop-scoped variables in a loop
- assume (%var.type is "Var") or barf "Loop expected variable, not: \%var"
+ unless (%var.type is "Var"): compile error at %var.source "Loop expected variable, not: %s"
%lua = (..)
Lua ".."
for \(%var as lua expr)=\(%start as lua expr),\(%stop as lua expr),\(%step as lua expr) do
@@ -185,12 +185,11 @@ compile [..]
parse [for %var in %start to %stop %body] as (..)
for %var in %start to %stop via 1 %body
-
# For-each loop (lua's "ipairs()")
compile [for %var in %iterable %body] to:
# This uses Lua's approach of only allowing loop-scoped variables in a loop
- assume (%var.type is "Var") or barf "Loop expected variable, not: \%var"
+ unless (%var.type is "Var"): compile error at %var.source "Loop expected variable, not: %s"
%lua = (..)
Lua ".."
for i,\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do
@@ -223,8 +222,8 @@ compile [for %key = %value in %iterable %body, for %key %value in %iterable %bod
..to:
# This uses Lua's approach of only allowing loop-scoped variables in a loop
- assume (%key.type is "Var") or barf "Loop expected variable, not: \%key"
- assume (%value.type is "Var") or barf "Loop expected variable, not: \%value"
+ unless (%key.type is "Var"): compile error at %key.source "Loop expected variable, not: %s"
+ unless (%value.type is "Var"): compile error at %value.source "Loop expected variable, not: %s"
%lua = (..)
Lua ".."
for \(%key as lua identifier),\(%value as lua identifier) in pairs(\(%iterable as lua expr)) do
@@ -266,101 +265,88 @@ compile [for %key = %value in %iterable %body, for %key %value in %iterable %bod
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-# Switch statement/multi-branch if
-compile [when %body] to:
+# Multi-branch conditional (if..elseif..else)
+compile [if %body, when %body] to:
%code = (Lua "")
- %fallthroughs = []
- %is_first = (yes)
- %seen_else = (no)
- %branches = (%body if (%body.type == "Block") else [%body])
- for %func_call in %branches:
- assume (%func_call.type is "Action") or barf "Invalid format for 'when' statement. Only '*' blocks are allowed."
- with {%star: %func_call.1, %condition: %func_call.2, %action: %func_call.3}:
- assume (%star == "*") or barf "Invalid format for 'when' statement. Lines must begin with '*'"
- assume %condition or barf ".."
- Invalid format for 'when' statement. Lines must begin with '*' and have a condition \
- ..or the word "else"
-
- if (%action is (nil)):
- lua> "table.insert(\%fallthroughs, \(%condition as lua expr))"
- do next %func_call
-
- if (%condition == "else"):
- assume (not %is_first) or barf "'else' clause cannot be first in 'when % = ?' block"
- to %code write "\nelse\n "
- to %code write (%action as lua statements)
- %seen_else = (yes)
- ..else:
- assume (not %seen_else) or barf "'else' clause needs to be last in 'when' block"
- lua> "table.insert(\%fallthroughs, \(%condition as lua expr))"
- to %code write "\("if" if %is_first else "\nelseif") "
- for %i = %condition in %fallthroughs:
- if (%i > 1): to %code write " or "
- to %code write %condition
-
- to %code write " then\n "
- to %code write (%action as lua statements)
-
- %fallthroughs = []
- %is_first = (no)
+ %clause = "if"
+ %else_allowed = (yes)
+ unless (%body.type is "Block"): compile error at %body.source "'if' expected a Block, but got: %s"
+ for %line in %body:
+ unless (..)
+ ((%line.type is "Action") and ((length of %line) >= 2))
+ ..and (%line.(length of %line) is "Block" syntax tree)
+ ..:
+ compile error at %line.source ".."
+ Invalid line for 'if', each line should contain conditional expressions \
+ ..followed by a block, or "else" followed by a block:
+ %s
+ %action = %line.(length of %line)
+ if ((%line.1 is "else") and ((length of %line) == 2)):
+ unless %else_allowed: compile error at %line.source "Can't have two 'else' blocks"
+ unless ((length of "\%code") > 0):
+ compile error at %line.source "Can't have an 'else' block without a preceeding condition"
+ to %code write "\nelse\n \(%action as lua statements)"
+ %else_allowed = (no)
+ ..else:
+ to %code write "\%clause "
+ for %i in 1 to ((length of %line) - 1):
+ unless (%line.%i is syntax tree):
+ compile error at %line.source ".."
+ Invalid condition for 'if' statement:
+ %s
+ if (%i > 1): to %code write " or "
+ to %code write (%line.%i as lua expr)
+ to %code write " then\n \(%action as lua statements)"
+ %clause = "\nelseif"
- assume (%fallthroughs == []) or barf "Unfinished fallthrough conditions in 'when' block"
- assume ((length of "\%code") > 0) or barf "Empty body for 'when' block"
+ if ((length of "\%code") == 0):
+ compile error at %body.source "'if' block has an empty body"
to %code write "\nend --when"
return %code
-
# Switch statement
-compile [when %branch_value = ? %body, when %branch_value is? %body] to:
+compile [if %branch_value is %body, when %branch_value is %body] to:
%code = (Lua "")
- %fallthroughs = []
- %is_first = (yes)
- %seen_else = (no)
- %branches = (%body if (%body.type == "Block") else [%body])
- for %func_call in %branches:
- assume (%func_call.type is "Action") or barf "Invalid format for 'when' statement. Only '*' blocks are allowed."
- with {%star: %func_call.1, %condition: %func_call.2, %action: %func_call.3}:
- assume (%star == "*") or barf "Invalid format for 'when' statement. Lines must begin with '*'"
- assume %condition or barf ".."
- Invalid format for 'when' statement. Lines must begin with '*' and have a condition \
- ..or the word "else"
-
- if (%action is (nil)):
- lua> "table.insert(\%fallthroughs, \(%condition as lua expr))"
- do next %func_call
-
- if (%condition == "else"):
- assume (not %is_first) or barf "'else' clause cannot be first in 'when % = ?' block"
- to %code write "\nelse\n "
- to %code write (%action as lua statements)
- ..else:
- assume (not %seen_else) or barf "'else' clause needs to be last in 'when % = ?' block"
- to %code write "\("if" if %is_first else "\nelseif") "
- lua> "table.insert(\%fallthroughs, \(%condition as lua expr))"
- for %i = % in %fallthroughs:
- if (%i > 1): to %code write " or "
- if ((%.type is "Text") or (%.type is "Number")):
- to %code write "branch_value == \%"
- ..else: to %code write "utils.equivalent(branch_value, \%)"
-
- to %code write "then\n "
- to %code write (%action as lua statements)
-
- %fallthroughs = []
- %is_first = (no)
+ %clause = "if"
+ %else_allowed = (yes)
+ unless (%body.type is "Block"): compile error at %body.source "'if' expected a Block, but got: %s"
+ for %line in %body:
+ unless (..)
+ ((%line.type is "Action") and ((length of %line) >= 2))
+ ..and (%line.(length of %line) is "Block" syntax tree)
+ ..:
+ compile error at %line.source ".."
+ Invalid line for 'if % is % %', each line should contain expressions \
+ ..followed by a block, or "else" followed by a block:
+ %s
+ %action = %line.(length of %line)
+ if ((%line.1 is "else") and ((length of %line) == 2)):
+ unless %else_allowed: compile error at %line.source "Can't have two 'else' blocks"
+ unless ((length of "\%code") > 0):
+ compile error at %line.source "Can't have an 'else' block without a preceeding condition"
+ to %code write "\nelse\n \(%action as lua statements)"
+ %else_allowed = (no)
+ ..else:
+ to %code write "\%clause "
+ for %i in 1 to ((length of %line) - 1):
+ unless (%line.%i is syntax tree):
+ compile error at %line.source ".."
+ Invalid condition for 'if' statement:
+ %s
+ if (%i > 1): to %code write " or "
+ to %code write "branch_value == \(%line.%i as lua expr)"
+ to %code write " then\n \(%action as lua statements)"
+ %clause = "\nelseif"
- assume (%fallthroughs == []) or barf "Unfinished fallthrough conditions in 'when' block"
- assume ((length of "\%code") > 0) or barf "No body for 'when % = ?' block!"
- to %code write "\nend"
- %code = (..)
+ if ((length of "\%code") == 0):
+ compile error at %body.source "'if % is % %' block has an empty body"
+ to %code write "\nend --when"
+ return (..)
Lua ".."
- do --when % = ?
+ do --if % is
local branch_value = \(%branch_value as lua expr)
\%code
- end --when % = ?
-
- return %code
-
+ end --if % is
# Do/finally
compile [do %action] to (..)
generated by cgit v1.2.3 (git 2.25.1) at 2026-03-01 08:28:05 +0000