bufio: make scanning bounded and incremental

test/wcc/data/r700_bufio_scanline_discard/case.ww

@@ -2,6 +2,7 @@
 // Migrated from 700_e2e row 104.
 package main;
 import bufio;
+import errors;
 import io;
 import memio;
 fn main() i32 = {
@@ -14,26 +15,26 @@ fn main() i32 = {
   let buf: [16]u8;
   let sc:  bufio.scanner = bufio.newscannerbuf(m, buf[0:16]);
   let acc: i32 = 0;
-  let l1: (str | io.eof | io.error | bufio.overflow) = bufio.scanline(&sc);
+  let l1: (str | io.eof | io.error | errors.overflow) = bufio.scanline(&sc);
   match (l1) {
     case let s: str       => acc += s.len;
     case io.eof           => acc += -100;
     case let _e: io.error => acc += -1000;
-    case bufio.overflow   => acc += -10000;
+    case errors.overflow   => acc += -10000;
   };
-  let l2: (str | io.eof | io.error | bufio.overflow) = bufio.scanline(&sc);
+  let l2: (str | io.eof | io.error | errors.overflow) = bufio.scanline(&sc);
   match (l2) {
     case let s: str       => acc += s.len;
     case io.eof           => acc += -100;
     case let _e: io.error => acc += -1000;
-    case bufio.overflow   => acc += -10000;
+    case errors.overflow   => acc += -10000;
   };
-  let l3: (str | io.eof | io.error | bufio.overflow) = bufio.scanline(&sc);
+  let l3: (str | io.eof | io.error | errors.overflow) = bufio.scanline(&sc);
   match (l3) {
     case let s: str       => acc += -100;
     case io.eof           => acc += 7;
     case let _e: io.error => acc += -1000;
-    case bufio.overflow   => acc += -10000;
+    case errors.overflow   => acc += -10000;
   };
   return acc;
 };

test/wcc/data/r778_scanner_byte_bytes/case.ww

@@ -3,6 +3,7 @@
 package main;
 import os;
 import bufio;
+import errors;
 import memio;
 import io;
 export fn main() i32 = {
@@ -18,20 +19,20 @@ export fn main() i32 = {
     case let b: u8 => { fb = b; };
     case io.eof => { return 81; };
     case let e: io.error => { return 82; };
-    case bufio.overflow => { return 92; };
+    case errors.overflow => { return 92; };
     };
     if (fb != 65u8) { return 83; };
     match (bufio.scanbytes(&sc, 44u8)) {
     case let bs: []u8 => { if (bs.len != 1 || bs[0] != 66u8) { return 84; }; };
     case io.eof => { return 85; };
     case let e: io.error => { return 86; };
-    case bufio.overflow => { return 87; };
+    case errors.overflow => { return 87; };
     };
     match (bufio.scanbytes(&sc, 44u8)) {
     case let bs: []u8 => { if (bs.len != 2 || bs[0] != 67u8 || bs[1] != 68u8) { return 88; }; };
     case io.eof => { return 89; };
     case let e: io.error => { return 90; };
-    case bufio.overflow => { return 91; };
+    case errors.overflow => { return 91; };
     };
     return 53;
 };

test/wcc/data/r778_scanner_lines/case.ww

@@ -3,6 +3,7 @@
 package main;
 import os;
 import bufio;
+import errors;
 import memio;
 import io;
 export fn main() i32 = {
@@ -19,19 +20,19 @@ export fn main() i32 = {
     case let s: str => { if (s.len == 2 && s[0] == 97u8 && s[1] == 98u8) { ok += 1; }; };
     case io.eof => { return 81; };
     case let e: io.error => { return 82; };
-    case bufio.overflow => { return 83; };
+    case errors.overflow => { return 83; };
     };
     match (bufio.scanline(&sc)) {
     case let s: str => { if (s.len == 1 && s[0] == 99u8) { ok += 1; }; };
     case io.eof => { return 84; };
     case let e: io.error => { return 85; };
-    case bufio.overflow => { return 86; };
+    case errors.overflow => { return 86; };
     };
     match (bufio.scanline(&sc)) {
     case let s: str => { return 87; };
     case io.eof => { ok += 1; };
     case let e: io.error => { return 88; };
-    case bufio.overflow => { return 89; };
+    case errors.overflow => { return 89; };
     };
     bufio.finish(&sc);
     if (ok != 3) { return 90; };