use custom errors

Author: dragoncoder047

schemascii/__main__.py

@@ -1,12 +1,16 @@
 import argparse
 import sys
 from . import render, __version__
+from .errors import Error
 
 
 def cli_main():
     ap = argparse.ArgumentParser(
         prog="schemascii",
         description="Render ASCII-art schematics into SVG.")
+    ap.add_argument("-V", "--version",
+                    type="version",
+                    version=__version__)
     ap.add_argument("in_file",
                     help="File to process.")
     ap.add_argument("-o", "--out",
@@ -18,8 +22,8 @@ def cli_main():
         args.out_file = args.in_file + ".svg"
     try:
         result_svg = render(args.in_file)
-    except Exception as e:
-        print("error:", e, file=sys.stderr)
+    except Error as err:
+        print(repr(err), file=sys.stderr)
         sys.exit(1)
     with open(args.out_file, "w", encoding="utf-8") as out:
         out.write(result_svg)

schemascii/components.py

@@ -1,6 +1,8 @@
 import re
 from .grid import Grid
 from .utils import Cbox, BOMData
+from .errors import DiagramSyntaxError, BOMError
+
 
 SMALL_COMPONENT_OR_BOM = re.compile(r'#*([A-Z]+)(\d+|\.\w+)(:[^\s]+)?#*')
 
@@ -47,22 +49,22 @@ def find_big(grid: Grid) -> tuple[list[Cbox], list[BOMData]]:
                         y2 = j
                         break
                     if not cs[0] == cs[-1] == ':':
-                        raise SyntaxError(
+                        raise DiagramSyntaxError(
                             f'{grid.filename}: Fragmented box '
                             f'starting at line {y1 + 1}, col {x1 + 1}')
                 else:
-                    raise SyntaxError(
+                    raise DiagramSyntaxError(
                         f'{grid.filename}: Unfinished box '
                         f'starting at line {y1 + 1}, col {x1 + 1}')
                 inside = grid.clip(complex(x1, y1), complex(x2, y2))
                 results, resb = find_small(inside)
                 if len(results) == 0 and len(resb) == 0:
-                    raise ValueError(
+                    raise BOMError(
                         f'{grid.filename}: Box starting at '
                         f'line {y1 + 1}, col {x1 + 1} is '
                         f'missing reference designator')
                 if len(results) != 1 and len(resb) != 1:
-                    raise ValueError(
+                    raise BOMError(
                         f'{grid.filename}: Box starting at '
                         f'line {y1 + 1}, col {x1 + 1} has '
                         f'multiple reference designators')
@@ -95,9 +97,9 @@ def find_all(grid: Grid) -> tuple[list[Cbox], list[BOMData]]:
 
 
 if __name__ == '__main__':
-    grid = Grid("test_data/test_resistors.txt")
-    bbb, _ = find_all(grid)
+    test_grid = Grid("test_data/test_resistors.txt")
+    bbb, _ = find_all(test_grid)
     all_pts = []
     for box in bbb:
         all_pts.extend([box.p1, box.p2])
-    grid.spark(*all_pts)
+    test_grid.spark(*all_pts)

schemascii/components_render.py

@@ -2,9 +2,9 @@
 from cmath import phase, rect
 from math import pi
 from .utils import (Cbox, Terminal, BOMData, XML, Side,
-                   polylinegon, id_text, make_text_point,
-                   bunch_o_lines, deep_transform, make_plus, make_variable)
-from .metric import format_metric_unit
+                    polylinegon, id_text, make_text_point,
+                    bunch_o_lines, deep_transform, make_plus, make_variable)
+from .errors import TerminalsError, BOMError, UnsupportedComponentError
 
 RENDERERS = {}
 
@@ -31,7 +31,7 @@ def n_check(
                 bom_data: list[BOMData],
                 **kwargs):
             if len(terminals) != n_terminals:
-                raise TypeError(
+                raise TerminalsError(
                     f"{box.type}{box.id} component can only "
                     f"have {n_terminals} terminals")
             return func(box, terminals, bom_data, **kwargs)
@@ -47,7 +47,7 @@ def de_ambiguous(
             bom_data: list[BOMData],
             **kwargs):
         if len(bom_data) > 1:
-            raise ValueError(
+            raise BOMError(
                 f"Ambiguous BOM data for {box.type}{box.id}: {bom_data!r}")
         return func(
             box,
@@ -66,7 +66,7 @@ def sort_terminals(
             bom_data: list[BOMData],
             **kwargs):
         if len(terminals) != 2:
-            raise TypeError(
+            raise TerminalsError(
                 f"{box.type}{box.id} component can only "
                 f"have 2 terminals")
         if terminals[1].flag == '+':
@@ -261,8 +261,7 @@ def render_component(
         **kwargs):
     "Render the component into an SVG string."
     if box.type not in RENDERERS:
-        raise NameError(
-            f"Unsupported component type: {box.type}")
+        raise UnsupportedComponentError(box.type)
     return XML.g(
         RENDERERS[box.type](box, terminals, bom_data, **kwargs),
         class_=f"component {box.type}"

schemascii/errors.py

@@ -0,0 +1,18 @@
+class Error(Exception):
+    "A generic Schemascii error."
+
+
+class DiagramSyntaxError(SyntaxError, Error):
+    "Bad formatting in Schemascii diagram syntax."
+
+
+class TerminalsError(TypeError, Error):
+    "Incorrect usage of terminals on this component."
+
+
+class BOMError(ValueError, Error):
+    "Problem with BOM data for a component."
+
+
+class UnsupportedComponentError(NameError, Error):
+    "Component type is not supported."