From 6a5fce18fea83362743a5a50e1d18e903b602a76 Mon Sep 17 00:00:00 2001
From: Mikkel Troels Kongsted <mtkongsted@gmail.com>
Date: Thu, 23 Jan 2025 13:58:07 +0100
Subject: [PATCH] pretty report printing

---
 compiler/ctx.ts              | 22 ++++++++++++++++-
 compiler/diagnostics.ts      | 47 +++++++++++++++++++++++++++++++++---
 compiler/test_diagnostics.ts | 41 +++++++++++++++++++++++++++++--
 3 files changed, 104 insertions(+), 6 deletions(-)

diff --git a/compiler/ctx.ts b/compiler/ctx.ts
index 001378c..74d9311 100644
--- a/compiler/ctx.ts
+++ b/compiler/ctx.ts
@@ -1,5 +1,5 @@
 import * as ast from "./ast/mod.ts";
-import { prettyPrintReport, printStackTrace, Report } from "./diagnostics.ts";
+import { Pos, prettyPrintReport, printStackTrace, Report, Span } from "./diagnostics.ts";
 
 export class Ctx {
     private fileIds = new Ids();
@@ -43,6 +43,26 @@ export class Ctx {
         return this.files.get(id(file))!;
     }
 
+    public filePosLineText(file: File, pos: Pos): string {
+        const fileTextLines = this.fileInfo(file).text.split("\n")
+        return fileTextLines[pos.line-1]
+    }
+
+    public fileSpanText(file: File, span: Span): string {
+        let result = ""
+        const fileTextLines = this.fileInfo(file).text.split("\n")
+
+        for(let i = 0; i < fileTextLines.length; i++) {
+            if (i > span.end.line-1) {
+                break;
+            }
+            if (i >= span.begin.line-1) {
+                result += fileTextLines[i] + "\n";
+            }
+        }
+        return result
+    }
+
     public report(rep: Report) {
         this.reports.push(rep);
         this.reportImmediately(rep);
diff --git a/compiler/diagnostics.ts b/compiler/diagnostics.ts
index 6170397..8c7f9d7 100644
--- a/compiler/diagnostics.ts
+++ b/compiler/diagnostics.ts
@@ -1,4 +1,5 @@
 import { Ctx, File } from "./ctx.ts";
+import { exhausted } from "./util.ts";
 
 export type Span = {
     begin: Pos;
@@ -20,14 +21,54 @@ export type Report = {
     pos?: Pos;
 };
 
+function severityColor(severity: "fatal" | "error" | "warning" | "info") {
+    switch (severity) {
+        case "fatal":
+            return "\x1b[1m\x1b[31m";
+        case "error":
+            return "\x1b[1m\x1b[31m";
+        case "warning":
+            return "\x1b[1m\x1b[33m";
+        case "info":
+            return "\x1b[1m\x1b[34m";
+        }
+    exhausted(severity)
+}
+
 export function prettyPrintReport(ctx: Ctx, rep: Report) {
     const { severity, msg } = rep;
-    const origin = rep.origin ? `${rep.origin}: ` : "";
-    console.error(`${origin}${severity}: ${msg}`);
+    const origin = rep.origin ? `\x1b[1m${rep.origin}:\x1b[0m ` : "";
+    console.error(`${origin}${severityColor(severity)}${severity}:\x1b[0m \x1b[37m${msg}\x1b[0m`);
     if (rep.file && (rep.span || rep.pos)) {
+        const errorLineOffset = 2
         const { absPath: path } = ctx.fileInfo(rep.file);
         const { line, col } = rep.span?.begin ?? rep.pos!;
-        console.error(`    at ./${path}:${line}:${col}`);
+        console.error(`    --> ./${path}:${line}:${col}`);
+        if (rep.span) {
+            const spanLines = ctx.fileSpanText(rep.file, rep.span).split("\n");
+            spanLines.pop()
+            if (spanLines.length == 1) {
+                console.error(`${rep.span.begin.line.toString().padStart(4, ' ')}| ${spanLines[0]}`);
+                console.error(`    | ${severityColor(severity)}${" ".repeat(rep.span.begin.col)}${"~".repeat(rep.span.end.col-rep.span.begin.col)}\x1b[0m`)
+                return
+            }
+            for (let i = 0; i < spanLines.length; i++) {
+                console.error(`${(rep.span.begin.line+i).toString().padStart(4, ' ')}| ${spanLines[i]}`);
+                if (i == 0) {
+                    console.error(`    | ${" ".repeat(rep.span.begin.col-1)}${severityColor(severity)}${"~".repeat(spanLines[i].length-(rep.span.begin.col-1))}\x1b[0m`)
+                }
+                else if (i == spanLines.length-1) {
+                    console.error(`    | ${severityColor(severity)}${"~".repeat(rep.span.end.col)}\x1b[0m`)
+                }
+                else {
+                    console.error(`    | ${severityColor(severity)}${"~".repeat(spanLines[i].length)}\x1b[0m`)
+                }
+            }
+        }
+        else if (rep.pos) {
+            console.error(`${rep.pos.line.toString().padStart(4, ' ')}| ${ctx.filePosLineText(rep.file, rep.pos)}`);
+            console.error(`    | ${severityColor(severity)}${" ".repeat(rep.pos.col)}^\x1b[0m`)
+        }
     }
 }
 
diff --git a/compiler/test_diagnostics.ts b/compiler/test_diagnostics.ts
index 8b0bfd9..fb7d7dc 100644
--- a/compiler/test_diagnostics.ts
+++ b/compiler/test_diagnostics.ts
@@ -7,6 +7,14 @@ const text = `
 make an error here
 `;
 
+const biggerText = `
+dont make error here
+not here but start error here
+and here
+also here but not here
+or here
+`
+
 const file = ctx.addFile(
     "root",
     "path/file.ts",
@@ -15,13 +23,42 @@ const file = ctx.addFile(
     text,
 );
 
+const biggerFile = ctx.addFile(
+    "root",
+    "path/file.ts",
+    "path/file.ts",
+    undefined,
+    biggerText,
+);
+
 prettyPrintReport(ctx, {
     file,
     msg: "an error",
+    severity: "fatal",
+    origin: "compiler",
+    span: {
+        begin: { idx: 5, line: 2, col: 5 },
+        end: { idx: 13, line: 2, col: 13 },
+    },
+});
+
+prettyPrintReport(ctx, {
+    file: biggerFile,
+    msg: "an error",
     severity: "error",
     origin: "compiler",
     span: {
-        begin: { idx: 6, line: 2, col: 6 },
-        end: { idx: 13, line: 2, col: 13 },
+        begin: { idx: 6, line: 3, col: 14 },
+        end: { idx: 13, line: 5, col: 13 },
+    },
+});
+
+prettyPrintReport(ctx, {
+    file,
+    msg: "an error",
+    severity: "warning",
+    origin: "compiler",
+    pos: {
+        idx: 6, line: 2, col: 8 
     },
 });