🐐 Array slicing

tests.py

@@ -11,7 +11,7 @@ from parameterized import parameterized
 from fractions import Fraction
 
 from centvrion.ast_nodes import (
-  ArrayIndex, Bool, BinOp, BuiltIn, DataArray, DataDict, DataRangeArray,
+  ArrayIndex, ArraySlice, Bool, BinOp, BuiltIn, DataArray, DataDict, DataRangeArray,
   Defini, Continva, Designa, DesignaDestructure, DesignaIndex, DumStatement,
   Erumpe, ExpressionStatement, Fvnctio, ID, InterpolatedString, Invoca,
   ModuleCall, Nullus, Numeral, PerStatement, Program, Redi, SiStatement,
@@ -673,6 +673,15 @@ error_tests = [
   ("DESIGNA a, b VT III", CentvrionError),                                 # destructure non-array
   ("DESIGNA a, b VT [I]", CentvrionError),                                # destructure length mismatch: too many targets
   ("DESIGNA a, b VT [I, II, III]", CentvrionError),                       # destructure length mismatch: too few targets
+  ("[I, II, III][II VSQVE IV]", CentvrionError),                           # slice upper bound out of range
+  ("[I, II, III][NVLLVS VSQVE II]", CentvrionError),                      # slice with non-integer bound
+  ("I[I VSQVE II]", CentvrionError),                                      # slice on non-array
+  ("[I, II, III][III VSQVE I]", CentvrionError),                           # slice from > to
+  ("CVM SVBNVLLA\n[I, II, III][-I VSQVE II]", CentvrionError),            # slice with negative lower bound
+  ("CVM SVBNVLLA\n[I, II, III][I VSQVE -I]", CentvrionError),             # slice with negative upper bound
+  ("CVM FRACTIO\n[I, II, III][IIIS VSQVE III]", CentvrionError),          # slice with fractional lower bound
+  ("CVM FRACTIO\n[I, II, III][I VSQVE IIIS]", CentvrionError),            # slice with fractional upper bound
+  ("CVM FRACTIO\n[I, II, III][I / II VSQVE III]", CentvrionError),        # slice with division-fraction lower bound
 ]
 
 class TestErrors(unittest.TestCase):
@@ -1517,6 +1526,63 @@ class TestArrayIndexAssign(unittest.TestCase):
     run_test(self, source, nodes, value)
 
 
+# --- Array slicing ---
+
+array_slice_tests = [
+  # basic slice from middle
+  ("[X, XX, XXX, XL, L][II VSQVE IV]",
+    Program([], [ExpressionStatement(ArraySlice(
+      DataArray([Numeral("X"), Numeral("XX"), Numeral("XXX"), Numeral("XL"), Numeral("L")]),
+      Numeral("II"), Numeral("IV")))]),
+    ValList([ValInt(20), ValInt(30), ValInt(40)])),
+  # slice of length 1
+  ("[I, II, III][II VSQVE II]",
+    Program([], [ExpressionStatement(ArraySlice(
+      DataArray([Numeral("I"), Numeral("II"), Numeral("III")]),
+      Numeral("II"), Numeral("II")))]),
+    ValList([ValInt(2)])),
+  # full array slice
+  ("[I, II, III][I VSQVE III]",
+    Program([], [ExpressionStatement(ArraySlice(
+      DataArray([Numeral("I"), Numeral("II"), Numeral("III")]),
+      Numeral("I"), Numeral("III")))]),
+    ValList([ValInt(1), ValInt(2), ValInt(3)])),
+  # slice on variable
+  ("DESIGNA a VT [I, II, III, IV, V]\na[II VSQVE IV]",
+    Program([], [
+      Designa(ID("a"), DataArray([Numeral("I"), Numeral("II"), Numeral("III"), Numeral("IV"), Numeral("V")])),
+      ExpressionStatement(ArraySlice(ID("a"), Numeral("II"), Numeral("IV"))),
+    ]),
+    ValList([ValInt(2), ValInt(3), ValInt(4)])),
+  # slice then index (chained)
+  ("[I, II, III, IV][I VSQVE III][II]",
+    Program([], [ExpressionStatement(ArrayIndex(
+      ArraySlice(
+        DataArray([Numeral("I"), Numeral("II"), Numeral("III"), Numeral("IV")]),
+        Numeral("I"), Numeral("III")),
+      Numeral("II")))]),
+    ValInt(2)),
+  # slice on range array
+  ("[I VSQVE X][III VSQVE VII]",
+    Program([], [ExpressionStatement(ArraySlice(
+      DataRangeArray(Numeral("I"), Numeral("X")),
+      Numeral("III"), Numeral("VII")))]),
+    ValList([ValInt(3), ValInt(4), ValInt(5), ValInt(6), ValInt(7)])),
+  # expression as slice bounds
+  ("[I, II, III, IV, V][I + I VSQVE II + II]",
+    Program([], [ExpressionStatement(ArraySlice(
+      DataArray([Numeral("I"), Numeral("II"), Numeral("III"), Numeral("IV"), Numeral("V")]),
+      BinOp(Numeral("I"), Numeral("I"), "SYMBOL_PLUS"),
+      BinOp(Numeral("II"), Numeral("II"), "SYMBOL_PLUS")))]),
+    ValList([ValInt(2), ValInt(3), ValInt(4)])),
+]
+
+class TestArraySlice(unittest.TestCase):
+  @parameterized.expand(array_slice_tests)
+  def test_array_slice(self, source, nodes, value):
+    run_test(self, source, nodes, value)
+
+
 # --- Comments ---
 
 comment_tests = [